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Hi,
I am trying to access its datasouce property after the gridview has been databind, but the value is always null.
here is the example I did:
in button1_click:
...
GridView1.DataSource = dataTable1;
GridView1.DataBind();
....
in button2_click:
....
DataTable dt = GridView1.DataSource;
....
The value of dt in button2_Click is always null. I read about that the data source needs to be bound to the GridView control only when the page is first loaded. Thereafter, the values are stored in view state.
How to access ViewState to get the data source property?
Is there anybody know about it?
Thanks in advance!
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The datasource isn't maintained in viewstate as a raw dataset.
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Datagrid is stored in a table, which is stored in ViewState.
ViewState doesn't store the DataTable. only serialized data can be stored in viewstate.
Pradipta Basu
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I think you may just have to cast the datasource to a datatable
DataTable dt = (DataTable)GridView1.DataSource;
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I did try that. But it still is null..
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I saved the datatable into viewstate when the GridView is binded. Then, when I want to use it, I just get it from viewState...
Do you think it could cause any issue, like perfomance?
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Storing multiple rows or even a single row with considerable no. of columns is going to create an impact on the page's performance.
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to dynamically add rows into GridView without really adding records into database, so that user can add as many rows as he wants, and dump all the rows into db at once.
Is there any other ideas to do it?
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Remember that you're actually storing the datatable twice (in a sense). It's values are being stored in the viewstate inside the binded control, and you are storing it, as a whole, also.
With minimal rows, this would be fine. But at the table grows, the viewstate grows twice as fast and could lead to major memory headaches down the road.
You also have the option of turning off viewstate for the binded control. There are several articles explaining this process.
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Need support....
I d'like to copy a file aspnetdb.mdf (ms sql 2005 db) created with microsoft visual web developer 2005 to my websites host. I have already a website copied with asp 2.0 sites to my host without problems.
But now it is the first time that i try to copy a ms sql 2005 db. The aspnetdb.mdf works fine on my local PC. Now the provider told me, that i have to create a db Login in his Control Panel for accessing sql 2005 server.
I have to define a Login user name and a password. And later a sql 2005 db.
My Problem: Why should i create an new sql 2005 db on the host server. I d'like to transfer my local sql 2005 db (microsoft visual web developer 2005) to the host?
What changes are necessary in the web.config:
The definition on my local pc:
<connectionStrings>
<add name="ASPNETDBConnectionString1" connectionString="Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\ASPNETDB.MDF;Integrated Security=True;User Instance=True" providerName="System.Data.SqlClient"/>
</connectionStrings>
Do I have to add a user id and a password?
What connection string is necessary to access to my host sql server?
Do you know some recommended tutorials? I could not see a solution in the following video:
http://www.asp.net/learn/videos/view.aspx?tabid=63&id=5
Thanks a lot for your support.
You see -- I am a beginner....
Best regards
ullk
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The provider might not have a way or the time to import SQL Express database into SQL Server 2005 Database. The database created by the provider is usually blank and you are required to re-create all the necessary objects through the provided interface
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I'm creating an on-line application that has a submit button. When submit action occurs, the form data is then submitted to a Positional Flat File. The reason why I have to use flat file is because the company that we outsourced for our recruiting database uses flat file text to input into the database. I have no idea how to submit form data to a positional flat file. I have to flat file template with the record lengths. Can anyone help?
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just create a sting of the record length. Then place each item in the string in the respective position. Another option is to pad each item to its max length, they append it to create the record.
You may want to consider creating a simple class that contains each field, then a create method to concatenate the individual fields to the record length.
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Is there code snippets that I can see to help me get started? Any tutorials or examples?
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I explained it clearly enough to get you started. It's pretty much scoped.
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I know that you explained it but I'm an extreme beginner. So I'm going to start with remedial questions. Is there a different forum that is for someone who is as remedial as myself? If not, I have a couple questions:
1. When I hit submit to call the action on my Application.asp page, I need to have a method which is post and my action which is??? That's where I'm lost, When I add a new item in Visual Studio, should it be a vbscript file?, jscript file?, a vb module? That's where I need to begin.
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If you're an extreme beginner programmer, how did you get this assignment in the first place?
Is it homework?
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No, it's an actual project. Our supervisor wanted to have one of us learn .net so I'm starting these classes soon but I have to start the project now. I have the form laid out with the validations, I'm just lost after that. Once the submit button is clicked, I'm lost, I have no idea what to do. I don't want to seem totally clueless so I don't get in trouble, so I'm trying really hard to figure it out. I have the flat file template with how many char lengths for each field. That's why I asked for tutorials or code snippets so I can learn from it. I don't want to frustrate people on this forum, I just need help starting out with this stuff.
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You have EVERYTHING you need. Create string values for each field. Pad them with blanks to get the desired length. Concatenate them to create the record. What else could you possibly need?
string field1;
....
field1.PadRight(fieldlength, " ");
fullrecord = field1 + field2...
Any programmer, that knows ANY programming language can grasp this.
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I don't have a language to grasp, that's the problem chief.
For Example:
Would it start like this:
<%
Dim Field1
Field1=Request.Form("first name")
string field1;
field1.PadRight(fieldlength,"20");
Do I have to declare anything? You have to understand that I'm in Kindergarden with this stuff.
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I don't mean this to be condescending, but you really need an ASP.NET book. There is no reason for Request.Form for this type of application. ASP.NET is event driven. You can create several textboxes for user input and a button. On the OnClick event of the button you do you actions.
(you can also set the MaxLength for each TextBox to the length of corresponding field)
If you're using VB.NET the declaration would be:
Button1_Click(...)
Dim WholeRecord as String
Dim Field1 as String
Dim Field2 as String
...
Field1 = Textbox1.Text
...
WholeRecord = Field1.PadRight( whateverThisFieldLengthIs, " ") + ...
That's basically it as far as creating the record.
Then you have your record to be saved.
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I bought the SAMS teach yourself ASP.NET in 21 days book but there is nothing about submitting form data to a flat file but maybe I need to look harder.
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I think you're worrying about the flat file concept too much. As a rudimentary test, try this:
Get the first 3 field names from the requirement.
In this example, I'll just call them Field1 thru Field3, but you would give them more descriptive names.
On the webform, add 3 textboxes (TextBox1 thru TextBox3).
In each Textbox's MaxLength property, set it to the field length (from the requirement) for this example I used (30,20 and 25, respectively) .
Now add a button and a label to the form (Button1 and Label1).
Double Click on the button to bring up the OnClick event code.
In the Button1_Click event, type the following.
string Field1;
string Field2;
string Field3;
string FlatRecord;
Field1 = TextBox1.Text;
Field2 = TextBox2.Text;
Field3 = TextBox2.Text;
FlatRecord = Field1.PadRight( 30, " ") + Field2.PadRight( 20, " ") + Field3.PadRight( 25, " ");
Label1.Text = FlatRecord;
Now, compile and run the project. Add some text to each textbox, and click the button. The result in Label1 will be a flat file record. There is really nothing to get hung up about.
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That's what I needed, Thanks. I just had to change some code around to declare DIM statements. It showed up in the label. Now how do I make the Flatrecord = a text file on the server? and I have to append to this file? I started reading the book and alot of stuff is making sense now.
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In your book, check out:
Day 13—Reading and Writing Files on the Web Server.
Using Files with ASP.NET. Including External Files. Accessing Files. Isolated Storage.
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