binding textbox with SqlDataSource

Hi,

I wants to bind textbox with sqldatasource in c#.net so I am using following code and has following error...

Exception Details:System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

Line 22:
Line 23: System.Data.DataView dv = (DataView) SqlDataSource1.Select(System.Web.UI.DataSourceSelectArguments.Empty);
Line 24: TextBox1.Text = dv[0]["Proid"].ToString();
Line 25:
Line 26: }

Please, anybody knows solution tell me

Show all your code here, please. Do you have the column "Proid" in your datasource and a TextBox1 in your ASPX page?