Re: Reflection and Linq Extension Methods - C# Discussion Boards

I would verify your WCF Service Project Name and/or your Namespaces. Also, in the rare case that you renamed the WCF Service Project, I've found it's wise to just start over (i.e. delete the project and create a brand new one with the name you want) vs. figuring out all the things you need to also rename behind the scenes.

Russ

Hi I'm trying to build a program which will read and assign to variables the values from an XML file which goes like this (without the *):
<*n1> random number here <*/n1>
<*n2> random number here <*/n2>
I tried to use the XmlTextReader but I got an error when I passed the location of the file
("C:\\Documents and Settings\\myfile.xml") so I tried the XmlDocument and it's function SelectSingleNode("n1") but I got another error.
So what's the best way to get the values from this XML file? (I also want to show an error message if the XML file is not built as I mentioned (<*n1> <*/n1> <*n2> <*/n2>).
thanks

gibsray wrote:
but I got an error when I passed the location of the file
I tried the XmlDocument and it's function SelectSingleNode("n1") but I got another error.

We can't read your mind. What errors did you receive?

/ravi

My new year resolution: 2048 x 1536
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ravib(at)ravib(dot)com

I very much doubt that your file is in the root of the Document and Settings folder. Perhaps you should double check that your path is valid.

I wasn't, now I am, then I won't be anymore.

You need a root. You did not provide the error, so so not know what the exact issue is, but can only have one root node.

XML

<items>
  <*n1>random number here </*n1>
   <*n2>random number here </*n2>
</items>

Of course this is not good xml either. XML will object to the *, and there is no * before the backslash.

Try this link

http://support.microsoft.com/kb/307548[^]

Smile | :)

I have this code:

XML

public static IQueryable<T> OrderBy<T>(
               this IQueryable<T> source, string propertyName, string order)
        {
            var type = typeof(T);
            var asc = order == "asc" ? true:false;
            string methodName = asc ? "OrderBy" : "OrderByDescending";

            var parameter = Expression.Parameter(type, "p");
            var property = type.GetProperty(propertyName);

            var propertyAccess = Expression.MakeMemberAccess(parameter, property);
            var orderByExp = Expression.Lambda(propertyAccess, parameter);

            MethodCallExpression resultExp = Expression.Call(typeof(Queryable), methodName,
                              new Type[] { type, property.PropertyType },
                              source.Expression, Expression.Quote(orderByExp));
            return source.Provider.CreateQuery<T>(resultExp);
        }

And i would like to extend it to allow child properties, like "Address.Street"
if i pass just a simple property it works nice... but i want to make it better and accept child object property to make order by.

Anyone knows how to modify it?
I tryed but no success... i don't know how to make it to find the child object property and create the MemberAccess with it Dead | X|

Thanks!!

There you go, sorts on properties of properties... not quite sure if it works with methods. The logic is there, but it's not fully tested

C#

public static IEnumerable<T> SortObject<T>(this IEnumerable<T> ObjectToSort, string SortBy)
   {
       if (ObjectToSort == null)
           return null;
       if (string.IsNullOrEmpty(SortBy) == true)
           return null;

       // Handle sorting on object methods as well as properties
       string[] tempSorts = SortBy.Split(',');
       List<string> SortList = new List<string>();
       bool inParanthese = false;
       string addString = string.Empty;
       foreach (string tempSort in tempSorts)
       {
           if ((tempSort.Contains("(") == true) && (tempSort.Contains(")") == false))
           {
               inParanthese = true;
           }
           else if (tempSort.Contains(")") == true)
           {
               inParanthese = false;
           }
           if (inParanthese == false)
           {
               if (string.IsNullOrEmpty(addString) == false)
               {
                   SortList.Add(addString + "," + tempSort.Trim());
               }
               else
               {
                   SortList.Add(tempSort);
               }
               addString = string.Empty;
           }
           else
           {
               if (string.IsNullOrEmpty(addString) == false)
                   addString += ",";
               addString += tempSort.Trim();
           }
       }
       string[] Sorts = SortList.ToArray();
       bool Sorted = false;
       foreach (string FieldSort in Sorts)
       {
           string[] SubSort = FieldSort.Trim().Split(' ');

           string[] props = SubSort[0].Split('.');
           Type type = typeof(T);
           ParameterExpression arg = Expression.Parameter(type, "x");
           Expression expr = arg;
           foreach (string prop in props)
           {
               System.Reflection.PropertyInfo pi = type.GetProperty(prop);
               if (pi != null)
               {
                   Sorted = true;
                   //expr = Expression.Property(expr, pi);
                   expr = Expression.MakeMemberAccess(expr, pi);
                   type = pi.PropertyType;
               }
               else
               {
                   // Handle sorting on object methods as well as properties
                   string wholeMethod = prop;
                   if ((wholeMethod.Contains("(") == false) && (wholeMethod.Contains(")") == false))
                   {
                       //Ensure that method is in the proper format
                       wholeMethod += "()";
                   }
                   int firstParans = wholeMethod.IndexOf('(');
                   int lastParans = wholeMethod.LastIndexOf(')');
                   if ((firstParans > -1) && (lastParans > firstParans))
                   {
                       //Parse out method name and parameters
                       string methodname = wholeMethod.Substring(0, firstParans).Trim();
                       string paramList = wholeMethod.Substring(firstParans + 1, lastParans - (firstParans + 1));

                       System.Reflection.MethodInfo mi = null;
                       List<string> indParams = null;
                       if (paramList.Length > 0)
                       {
                           //Found some parameters
                           bool inDoubleQuotes = false;
                           bool inSingleQuotes = false;
                           string currParam = string.Empty;
                           indParams = new List<string>();
                           //Parse each individual parameter into a list of strings
                           foreach (char c in paramList)
                           {
                               if (c == '\"')
                               {
                                   if (inSingleQuotes == false)
                                   {
                                       inDoubleQuotes = !inDoubleQuotes;
                                   }
                                   currParam += c;
                               }
                               else if (c == '\'')
                               {
                                   if (inDoubleQuotes == false)
                                   {
                                       inSingleQuotes = !inSingleQuotes;
                                   }
                                   currParam += c;
                               }
                               else if ((c == ',') && (inDoubleQuotes == false) && (inSingleQuotes == false))
                               {
                                   //end of parameter
                                   if (string.IsNullOrEmpty(currParam) == false)
                                   {
                                       indParams.Add(currParam);
                                       currParam = string.Empty;
                                   }
                               }
                               else
                               {
                                   currParam += c;
                               }
                           }
                           if ((string.IsNullOrEmpty(currParam) == false) && (inDoubleQuotes == false) &&
                               (inSingleQuotes == false))
                           {
                               indParams.Add(currParam);
                           }
                           Type[] methodTypes = new Type[indParams.Count];
                           Expression[] methodParams = new Expression[indParams.Count];
                           int paramTypeIndex = 0;
                           int intResult;
                           //Determine parameter types and values for each parameter
                           foreach (string indParam in indParams)
                           {
                               if (indParam[0] == '\'')
                               {
                                   if ((indParam.Length == 3) && (indParam[2] == '\''))
                                   {
                                       //char
                                       methodTypes[paramTypeIndex] = typeof(char);
                                       methodParams[paramTypeIndex] = Expression.Constant(indParam[1], typeof(char));
                                   }
                                   else
                                   {
                                       //Invalid char so do as string
                                       methodTypes[paramTypeIndex] = typeof(string);
                                       methodParams[paramTypeIndex] = Expression.Constant(indParam, typeof(string));
                                   }
                               }
                               else if (indParam[0] == '"')
                               {
                                   //string
                                   methodTypes[paramTypeIndex] = typeof(string);
                                   methodParams[paramTypeIndex] = Expression.Constant(indParam, typeof(string));
                               }
                               else if (int.TryParse(indParam, out intResult) == true)
                               {
                                   //Int
                                   methodTypes[paramTypeIndex] = typeof(int);
                                   methodParams[paramTypeIndex] = Expression.Constant(intResult, typeof(int));
                               }
                               else
                               {
                                   methodTypes[paramTypeIndex] = typeof(object);
                                   methodParams[paramTypeIndex] = Expression.Constant(indParam);
                               }
                               paramTypeIndex++;
                           }
                           //Get the method
                           mi = type.GetMethod(methodname, methodTypes);
                           if (mi != null)
                           {
                               //Add the method with parameters to the dynamic LINQ expression
                               expr = Expression.Call(expr, mi, methodParams);
                           }
                       }
                       else
                       {
                           //No parameters for this method
                           mi = type.GetMethod(methodname, System.Type.EmptyTypes);
                           if (mi != null)
                           {
                               //Add the method to the dynamic LINQ expression
                               expr = Expression.Call(expr, mi);
                           }
                       }
                   }
               }
           }
           LambdaExpression lambda = Expression.Lambda(expr, arg);
           if (Sorted == true)
           {
               //Sorted = true;
               IQueryable<T> queryableData = ObjectToSort.AsQueryable<T>();
               if ((SubSort.Count() > 1) && (string.Compare(SubSort[1].Trim(), "desc", true) == 0))
               {
                   MethodCallExpression MyExpr = Expression.Call(
                       typeof(Queryable), "OrderByDescending",
                       new Type[] { typeof(T), type },
                       queryableData.Expression, lambda);
                   IQueryable<T> results = queryableData.Provider.CreateQuery<T>(MyExpr);
                   try
                   {
                       //Trying to determine when sub-property is a nullable object how to
                       //get the sort results without a NullReferenceException error
                       //Getting the count() throws the error if the sort is performed on a
                       //sub-property of a nullable object that is the property of the main object
                       results.Count();
                       ObjectToSort = results;
                   }
                   catch (Exception exc){}
                   //ObjectToSort = ObjectToSort.OrderByDescending(lambda);
                   //ObjectToSort = ObjectToSort.OrderByDescending(i => propInfo.GetValue(i, null));
               }
               else
               {
                   MethodCallExpression MyExpr = Expression.Call(
                       typeof(Queryable), "OrderBy",
                       new Type[] { typeof(T), type },
                       queryableData.Expression, Expression.Quote(lambda));
                   IQueryable<T> results = queryableData.Provider.CreateQuery<T>(MyExpr);
                   try
                   {
                       //Trying to determine when sub-property is a nullable object how to
                       //get the sort results without a NullReferenceException error
                       //Getting the count() throws the error if the sort is performed on a
                       //sub-property of a nullable object that is the property of the main object
                       results.Count();
                       ObjectToSort = results;
                   }
                   catch (Exception exc){}
                   //ObjectToSort = ObjectToSort.OrderBy(x => expr);
                   //ObjectToSort = ObjectToSort.OrderBy(i => propInfo.GetValue(i, null));
               }
           }
       }
       if (Sorted == true)
       {
           //Found at least one property to sort on in SortBy string
           return ObjectToSort;
       }
       else
       {
           //No valid properties found to sort on in SortBy string
           return null;
       }
   }

So my current project here at work will soon involve a parts ordering process. All is well with that. I'm just looking for all possible solutions for one portion of that process. Here is the gist of how it will work:

Worker #1: "Oh, I need to order this part."
------ * Select the part(s) using a CheckBox
------ * Click 'Place Order'

Worker #2 (picker) is in his station in some other work area. What needs to happen is when Worker #1 clicks 'Place Order', a label will print out at Worker #2's station with the appropriate information. Now, the label format and such is not the problem. What I am looking for is the most efficient method for monitoring the orders and printing the label automatically. I hope that was explained clearly.

When an order is placed it will be inserted into a table in Microsoft SQL Server 2008. And this is a WinForms application (C#, .NET v4.0).

The first potential solution I have contemplated: A Windows Service on Worker #2's station which monitors the database for new orders, set to check every so often (fairly short intervals).

My second potential solution: Share Worker #2's printer on the local network and connect to it via each station which can place orders.

What can you all suggest that may help me along? If you need anymore information please feel free to ask. I will gladly provide further information. Smile | :)

djj55: Nice but may have a permission problem
Pete O'Hanlon: He has my permission to run it.

Matt U. wrote:
What I am looking for is the most efficient method for monitoring the orders and printing the label automatically. I hope that was explained clearly.

Depends on where your orders are stored.

Matt U. wrote:
When an order is placed it will be inserted into a table in Microsoft SQL Server 2008.

Query Notification[^] Smile | :)

Matt U. wrote:
The first potential solution I have contemplated: A Windows Service on Worker #2's station which monitors

I'd recommend a user-level application, not a service. It does not need to run when there's no user, since there's nowhere to display the notification and no-one to react.

Bastard Programmer from Hell Suspicious | :suss:

if you can't read my code, try converting it here[^]

Awesome, thanks a ton, Eddy! I'll be bookmarking the link and reading into it. I appreciate the help. Smile | :)

djj55: Nice but may have a permission problem
Pete O'Hanlon: He has my permission to run it.

Also, I did forget to mention the fact that I am using LINQ To SQL. However, I found this article[^] which contains a basic explanation for using Query Notifications with LINQ To SQL. I had to make some modifications, as that article is several years old, but I got it working. Thanks again. Smile | :)

djj55: Nice but may have a permission problem
Pete O'Hanlon: He has my permission to run it.

Sounds like you should create a service and use a insert trigger: http://stackoverflow.com/questions/8874699/trigger-windows-service-when-the-new-record-insert-in-to-db[^]. It should also be possible to create a trigger and do this directly since can write triggers in c# (http://www.c-sharpcorner.com/UploadFile/pk_khuman/ManagedTrigersUsingCSharp02202007230729PM/ManagedTrigersUsingCSharp.aspx[^])

I'm having a problem ...

<br />
DataTable GetSomeData()<br />
{<br />
    DataTable dtResult = null;<br />
    IDbCommand Cmd = new SqlCommand(SQL, OldSqlConn);<br />
    DataAdapter da = new DataAdapter(Cmd);<br />
    DataSet ResultSet = new DataSet();<br />
    da.Fill(ResultSet);<br />
<br />
    if(ResultSet!=null)<br />
    {<br />
        dtResult = ResultSet.Tables(0);<br />
        foreach(DataRow rw in dtResult.Rows)<br />
        {<br />
           if(SomeConditionMet) {<br />
              rw["SomeCol"] = xxxxx; << Blows up here saying Column 'SomeCol' does not belong to table ABC (But I'm quite confident SomeCol is a column which should be returned by the SQL query... wondering if it's any issue with ADO.NET SqlConn caching or if OldSqlConn has any stale data at one point during the night app loses database connection or something... confused as I can't reproduce this on debugger and it happens only once in a month)<br />
           }<br />
        }<br />
     }<br />
<br />
    return dtResult;<br />
}<br />

dev

Is there any reason you don't open your db connection before use and close just after?
Preferably with:

C#

using (SqlConnection connection = new SqlConnection(connectionString))
    {
        connection.Open();
        // Do work here; connection closed on leaving scope.
    }

--
"My software never has bugs. It just develops random features."

Put a breakpoint on the line that causes you a problem. Expand the DataRow in the watch window and inspect the values that are in there.

In other words, learn how to use the debugger. It would save you a lot of time coming up with random ideas about what the issue could be.

*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier

that's the problem - i ran it on debugger whole night just can't reproduce this problem. It only happens once in a full moon

dev

devvvy wrote:
that's the problem - i ran it on debugger whole night just can't reproduce this problem. It only happens once in a full moon

Try logging all Sql statements that get executed.

I assume that you're not "keeping a connection open"? If yes, then you might want to try and see how the system reacts if the server goes to sleep.

Bastard Programmer from Hell Suspicious | :suss:

if you can't read my code, try converting it here[^]

From the look of it it feels like someone is changing schema of referenced table or view - SQL is same/constant and doesn't change. I try to log columns returned from ResultSet when this sh*t happens again. No joy thus far!

dev

devvvy wrote:
Column 'SomeCol' does not belong to table ABC

As others have stated you need to debug your code and I would suggest that you make sure that the query you are executing does return a column names that it is throwing an error on.

I would test this by executing your query in the database that you are using.

Lobster Thermidor aux crevettes with a Mornay sauce, served in a Provençale manner with shallots and aubergines, garnished with truffle pate, brandy and a fried egg on top and Spam - Monty Python Spam Sketch

Does anyone know how to send message to mobile(Windows phone 7) by using Web service (ASP.NET web service).
Now, I am doing a project about sending message automatically. I found for this, and I knew to API Google, but it only send message to one determine phone number. Can anyone help me?? I want to send message to multi person....Thank you so much!

You do realise that if you can send a message to one person there, you could just use the same call again to send the message to another person don't you?

*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier

I have downloaded the following code to work from for an app which requires login and registration.

http://code.msdn.microsoft.com/windowsdesktop/CCS-LABS-C-Creating-a-9ba05613/view/Discussions[^]

When I run the code and wish to register I enter my registration details and when I Click on register the MessageBox appear with note "Username can not be empty."
But there is text in the box.

Any suggestions?

Below is the code for the registration form.

C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace ccslabsLogIn.forms
{
    public partial class frmRegister : Form
    {

        #region "Properties"

        private bool _Registered = false;

        public bool Registered
        {
            get { return _Registered; }
            set { _Registered = value; }
        }
        private string _Username = "";

        public string Username
        {
            get { return _Username; }
            set { _Username = value; }
        }

        #endregion

        public frmRegister()
        {
            InitializeComponent();
        }

        private void btnCancel_Click(object sender, EventArgs e)
        {
            Registered = false; // tell calling form the user DID NOT register
            this.Close(); // close the form
        }

        // register the dude.
        private void btnRegister_Click(object sender, EventArgs e)
        {
            RegisterUser();
        }

        // Register the User
        private void RegisterUser()
        {
            if (tbUsername.Text.Length > 0) // You may want longer than 1 char minimum for usernames
            {
                if (tbPassword.Text != tbRepeatPassword.Text) { MessageBox.Show("Passwords do not match"); RegisterUser(); } // passwords do not match retry
                // ok passwords do match are they empty?
                if (tbPassword.Text.Length == 0) { MessageBox.Show("Passwords can not be empty"); RegisterUser(); } // empty passwords try again!
                // Ok username and passwords are valid.
                // register the user !
                usersTableAdapter.Insert(tbUsername.Text, tbPassword.Text);
                Registered = true;
                this.Close();
            }
            MessageBox.Show("Username can not be empty");
            RegisterUser();
        }

        private void usersBindingNavigatorSaveItem_Click(object sender, EventArgs e)
        {
            this.Validate();
            this.usersBindingSource.EndEdit();
            this.tableAdapterManager.UpdateAll(this.applicationDataSet);

        }

        private void frmRegister_Load(object sender, EventArgs e)
        {
            // TODO: This line of code loads data into the 'applicationDataSet.Users' table. You can move, or remove it, as needed.
            this.usersTableAdapter.Fill(this.applicationDataSet.Users);

        }
    }
}

Thank you very much.

Should be something like this, I reckon;

C#

        // Register the User
        private void RegisterUser()
        {
            if (tbUsername.Text.Length > 0) // You may want longer than 1 char minimum for usernames
            {
                if (tbPassword.Text != tbRepeatPassword.Text) { MessageBox.Show("Passwords do not match"); RegisterUser(); } // passwords do not match retry
                // ok passwords do match are they empty?
                if (tbPassword.Text.Length == 0) { MessageBox.Show("Passwords can not be empty"); RegisterUser(); } // empty passwords try again!
                // Ok username and passwords are valid.
                // register the user !
                usersTableAdapter.Insert(tbUsername.Text, tbPassword.Text);
                Registered = true;
                RegisterUser(); // moved!
                this.Close();
            }
            else
                 MessageBox.Show("Username can not be empty");
        }

Bastard Programmer from Hell Suspicious | :suss:

if you can't read my code, try converting it here[^]

Thanks a lot that did the trick.