ASP.NET Webform avoid loading datatable every Postback

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I have a WebForm that contain a GridView, a textbox and a button. When i press on the button the data of the text box is added to the GridView. This is my code:

C#

public partial class MyClass : System.Web.UI.Page
{
   Static DataTable dt = new DataTable();
   DataRow dr;
   protected void Page_Load(object sender, EventArgs e)
   {
      if(!IsPostBack)
      {
         dt.Columns.Add("ServiceName", typeof(string));
         GridView1.DataSource = dt;
      }

      GridView1.DataBind();
   }
   protected void btn_Click(object sender, ImageClickEventArgs e)
   {
      dr = dt.NewRow();
      dr["ServiceName"] = txtBox.Text;
      dt.Add(dr);
   }
}

The problem is that I've chosen to make the datatable to be a static not to recreate it in each postBack but as a result of saving the static variable in the memory the data is not cleared when refreshing the page (Create a new object from this page) and the data of the DataTable "dt" is bound to the gridview at the beginning .. what can I use instead of the static variable?
thanks in advance

Posted 1-Aug-13 0:48am

Hend Riad

Updated 1-Aug-13 1:06am

Joezer BH

v3

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3 solutions

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Tadit Dash (ତଡିତ୍ କୁମାର ଦାଶ) · Answer 1 · 2013-08-01T00:51:00

Solution 1

Use Session. Store DataTable in Session and retrieve and modify whenever you want.

Posted 1-Aug-13 0:51am

Tadit Dash (ତଡିତ୍ କୁମାର ଦାଶ)

Comments

Hend Riad 1-Aug-13 7:17am

is the session better than the static from the performance point of view ?

Tadit Dash (ତଡିତ୍ କୁମାର ଦାଶ) 1-Aug-13 7:31am

That will depend. If you have small amount of data, then using Session will not create any problem.

But if you have thousands of record, then using Session is not a good idea. You have think of other workarounds something like doing a custom pagination to get less data at a time for the Grid.

Vinay Mali · Answer 2 · 2013-08-01T00:52:00

Solution 2

Just avoid use of static.
you can use for loop for it.

Posted 1-Aug-13 0:52am

Vinay Mali

Comments

Hend Riad 1-Aug-13 7:18am

for loop is not solving the problem as the object is initialized each time i request the page

Harshil_Raval · Answer 3 · 2013-08-01T00:58:00

Solution 3

Hi,

Initialize DataTable object again in ispostback condition will solve your problem.

C#

protected void Page_Load(object sender, EventArgs e)
   {
      if(!IsPostBack)
      {
         dt=new DataTable(); // this will make your object null every time you load page.
         dt.Columns.Add("ServiceName", typeof(string));
         GridView1.DataSource = dt;
      }

      GridView1.DataBind();
   }

Posted 1-Aug-13 0:58am

Harshil_Raval

Comments

Hend Riad 1-Aug-13 7:25am

i'm trying it now

Hend Riad 1-Aug-13 7:32am

It fires exception : " Object reference not set to an instance of an object. " --> Null reference exception because at the first time the object is set to a value but in each postback it's not created it's just declared