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hi .. imanage to write my code on insert, update and delete fucntion in c#..
but why whenever i insert or update or delete the data..
it shows messagebox on this below
Operation is not valid while ItemsSource is in use. Access and modify elements with ItemsControl.ItemsSource instead.
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If you put the error message in quotes and google it, that's the best way to solve these sort of problems. It would be wise of you to post some code if you want more specific help, I can only guess at what your code looks like.
Specifying update/insert/delete SQL direct in code is easy, but it's not the way to go if you want to write professional quality code.
Christian Graus - Microsoft MVP - C++
"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )
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I have written a very basic windows application that connects to a mysql database, invoke some functions,write on the database and get a string as a result to be used in my program. This is a periodic event and I use timers to periodically invoke these functions. These program has users who needs to login and authentication is done in the database by the stored procedures and functions. I keep a track of log off times by invoking a function in the database by a timer every 30 seconds which basically updates the logout time when the proram is running so if the user loses the connection somehow, then I have a 0-30 seconds error margin for logout time.
But I think the program has some flaws. Firstly I heard that there are some programs that can actually show the code of an exe. I am worried that someone can easily see the code of my exe, get the username, password and adddess for the user and also the names of the functions and after writing a simple program like mine, can access, run and retrieve the data I want retrieve with my own program but my program only. I want to put security measures in my program but these does not make any sense if anyone can extract my exe code and alters my code to use in their own benefit.
My second question is actually regarding to the server and the database. The program has a default user for the mysql server that connects to the database (which only has execute privileges), and invokes the function. Is there a way to connect to a database with my program without actually including the database login & password & database name. Is there some way to do it like an asp page where I can just go to a webpage sending username and password for my program and that web page gives me the output string so that I can it in my program ( I can include a hidden web browser in my program).
please excuse me if my questions seem trivial but I am only a newbie and although I searched the forums and google, I could not find a straightforward answer. I have some ideas in my mind but if any of you have already been in my situation, then it would be a great help.
I will really appreciate any help
Thank you very much
andrew
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Andrew,
Have a google for a obfuscator. Also, if you dont already, you could keep your username/passwords and any other important data encrypted, there are plenty of examples on google and here of how to do that.
Regards,
Gareth.
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Hi,
I am basically trying to connect to a TomTom 520 and upload a new location/posistion. I have googled for stuff but whatever i google for TomTom, it just brings up places to buy it from.
Does anyone have any articles/info on if this is firstly possiable, and then how to do it.
Regards,
Gareth.
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I'd imagine that you'd need some sort of official API from TomTom to do that, the closest thing that I could find is here[^]. If that doesn't help then your best recourse may be to email TomTom and ask them directly.
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Hi Jimmanuel,
Thanks for the link. The SDK costs $195.00 and since this is a personal project, i think i'll just enter the locations with my fingers. Thanks for your help anyways!
Regards,
Gareth.
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hi i use c# wpf blend
in my combobox..there are two content.. shown below..
what should i do when the project is execute.. the "Name" will be displayed straight in the combobox.. instead of blank
<br />
<ComboBox Visibility="visible" Margin="17,25,14,0" x:Name="contact_combobox" VerticalAlignment="Top" Height="24" IsSynchronizedWithCurrentItem="True"><br />
<ComboBoxItem Content="Name"/><br />
<ComboBoxItem Content="Email"/><br />
</ComboBox>
2nd question
how to change textbox color in code behind..
this.textboxEmail.BackColor=Color.Yellow;
i cant find the .backcolor in wpf
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hi let me rephrase my question...
a combobox has 2 values..
name
email
when i run this project .. my problem is i don want to see
blank (first line)
name
email
i want to view it as
name
email
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Hi!
Just set the SelectedIndex or SelectedItem property of the combobox to the desired value.
Regards,
mav
--
Black holes are the places where God divided by 0...
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I get the following exception when I try to update my database It says:"Update requires a valid InsertCommand when passed DataRow collection with new rows."
and I dont know how to add the appropriated insert command.
Please help, thanks.
using System;<br />
using System.Collections.Generic;<br />
using System.ComponentModel;<br />
using System.Data;<br />
using System.Drawing;<br />
using System.Linq;<br />
using System.Text;<br />
using System.Windows.Forms;<br />
using System.Data.OleDb;<br />
using System.Data;<br />
<br />
namespace WindowsFormsApplication1<br />
{<br />
public partial class Form1 : Form<br />
{<br />
public Form1()<br />
{<br />
InitializeComponent();<br />
}<br />
<br />
private void button1_Click(object sender, EventArgs e)<br />
{<br />
OleDbConnection con = new OleDbConnection("Provider=Microsoft.Jet.Oledb.4.0;Data Source=E:\\hp\\Source\\Val-Asr-LastPart\\db1.mdb");<br />
con.Open();<br />
string sqlstr = "SELECT * FROM kham";<br />
OleDbCommand com=new OleDbCommand(sqlstr,con);<br />
OleDbDataAdapter da =new OleDbDataAdapter(com);<br />
DataSet ds = new DataSet();<br />
da.Fill(ds, "kham");<br />
DataRowCollection drc = ds.Tables["kham"].Rows;<br />
textBox1.Text = (string)drc[0][1];<br />
<br />
<br />
string str1 = (string)drc[0][1];<br />
string st="";<br />
string stt="";<br />
char[] ch1 = str1.ToCharArray();<br />
int k=0;<br />
int i=0;<br />
<br />
<br />
sqlstr="SELECT * FROM parsed";<br />
com.CommandText=sqlstr;<br />
da=null;<br />
da=new OleDbDataAdapter(com);<br />
ds=null;<br />
ds=new DataSet();<br />
da.Fill(ds,"parsed");<br />
for (; i < ch1.Length; i++)<br />
{<br />
if ((ch1[i] == '1' || ch1[i] == '2' || ch1[i] == '3' || ch1[i] == '4' || ch1[i] == '5' || ch1[i] == '6' || ch1[i] == '7' || ch1[i] == '8' || ch1[i] == '9' || ch1[i] == '0') && (ch1[i + 1] == '?'))<br />
{<br />
for(i++;i<ch1.length;i++)><br />
if ((ch1[i]!='(')||(ch1[i+1]!='['))<br />
st += ch1[i];<br />
else<br />
{<br />
for (i += 6; i < ch1.Length; i++)<br />
if ((ch1[i] == '1' || ch1[i] == '2' || ch1[i] == '3' || ch1[i] == '4' || ch1[i] == '5' || ch1[i] == '6' || ch1[i] == '7' || ch1[i] == '8' || ch1[i] == '9' || ch1[i] == '0') && (ch1[i + 1] == '?'))<br />
{<br />
string[] sst = { ""+(k++), st, stt };<br />
ds.Tables["parsed"].Rows.Add(sst);<br />
stt = "";<br />
i--;<br />
break;<br />
}<br />
else<br />
stt += ch1[i];<br />
break;<br />
}<br />
}<br />
<br />
}<br />
da.Update(ds,"parsed");
}<br />
}<br />
}<br />
</ch1.length;i++)>
modified on Saturday, January 05, 2008 9:31:30 AM
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This may be a hard question but i really wondered and needed. How can we make some certain wireless connections disappear from (winxp) existing wireless connections list. (for example i want to omit usr9600 connection). is this possible
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i have two combobox one of them is dependent to the other, how can i let the content of the first one change whenever i choose an opition from the second combobox.
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azza104 wrote: how can i let the content of the first one change whenever i choose an opition from the second combobox.
Write a handler for the first combobox's SelectionChangeCommited[^] event. In this handler, reset the contents of the second combobox.
/ravi
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thanx for your reply, i used the SelectedChangeCommitted but i don't have an efficient result.
this is my code:
at the designer.cs file:
this.combo_origion.SelectionChangeCommitted += new System.EventHandler(this.c);
and at the code file:
private void c(object sender, EventArgs e)
{
ComboBox com = (ComboBox)sender;
string selectedItem = combo_origion.SelectedText;
fill_locations(selectedItem);
}
/***************** at the following method the second combobox should change its content whenever the first one change the selected item ****/
private void fill_locations(string s) {
string st = combo_origion.Text;
SqlDataAdapter dtp = new SqlDataAdapter("get_locations", conn);
dtp.SelectCommand.CommandType = CommandType.StoredProcedure;
dtp.SelectCommand.Parameters.Add("@type_text", SqlDbType.NVarChar).Value = s;
DataSet chds = new DataSet();
dtp.Fill(chds);
combo_locations.DataSource = chds.Tables[0].DefaultView;
combo_locations.DisplayMember = "location";
combo_locations.ValueMember = "location_id";
//combo_locations.DataBind();
}
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i the previous method is true i fixed my database and its run now , but the changes happens after selecting the item two times...so do u know the problem here?
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Can anyone recommend a good book for self learning C#?
I'm looking for something that is reasonably up to date and has plenty of programming exercises to stretch the brain. I like the Deitel books because they have good exercises, but they cost too much and weigh a ton.
A book that includes multimedia programming would be good but not essential.
Thanks
James
Melbourne
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Personally I love this[^] book ... it doesn't really have any exercises but its a great foundation for learning C#.
It's currently in it's 4th edition having been updated each time for the various releases of C# and .Net and covers everything from your primative types to Linq 
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I'd second that recommendation. While it doesn't cover absolutely everything, it does give you enough to know how to accomplish most tasks, and it points you in the right direction when you need to go beyond "the basics".
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Any of the O'Reilly books are good. They don't usually have programming excercises like Deitel but they are excellent resources.
Scott.
—In just two days, tomorrow will be yesterday.
—Hey, hey, hey. Don't be mean. We don't have to be mean because, remember, no matter where you go, there you are. - Buckaroo Banzai
[ Forum Guidelines] [ Articles] [ Blog]
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Deitel it is then I think.
Thanks all for your responses.
James
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For newone in C# its good to study
Visual C# for dummies
also you can go for SAMS book i.e Teach yourself Visual C# in 21 days but as you said you want exercises then still i ll prefer Dietel book of csharp! You can have its electronic or soft version...
Wrox press's book "Beginning Visual C# 2005" is good too.
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Member 884411 wrote: Can anyone recommend a good book for self learning C#?
I've found that the Microsoft Press Step-by-Step series are really quite good.
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