Dynamically bind a grid (object not set to an instance of an object) error

Question

I have created grid dynamically and wanted to bind it.

I wanted to place grid in tabpanel.

I made following code for this purpose:

Protected Sub TabContainer1_ActiveTabChanged(ByVal sender As Object, ByVal e As System.EventArgs) 
    Handles TabContainer1.ActiveTabChanged
                Dim actTab As String = TabContainer1.ActiveTab.ID.ToString()
                Dim gv As GridView

                ds = gc.GetDataToListBinder("select * from ParameterOnline where TabName='Courts'")

                If actTab = "Panel_Courts" Then
                    gv.DataSource = ds.Tables(0)
                    TabContainer1.ActiveTab.Controls.Add(gv)
                End If


            End Sub

But its giving me error:

object not set to an instance of an object

By debugging i seen the dataset ds, but it is having all the necessary values in it.

I am not understanding where i am making mistake?

Answer in c# will also help me.

EDIT:

On gv.DataSource = ds.Tables(0) line i am getting error.

Almost all cases of `NullReferenceException` are the same. Please see "[What is a NullReferenceException in .NET?](http://stackoverflow.com/questions/4660142/what-is-a-nullreferenceexception-in-net)" for some hints. — John Saunders, Jul 21 '13 at 05:18

Adil · Accepted Answer · 2013-07-20T06:41:44.920

1

You are declaring the gridview but not instanstiating it. This article of creating gridview dynamically will helpful.

Change

Dim gv As GridView

To

Dim gv As GridView =  New GridView()

edited Jul 20 '13 at 06:41

answered Jul 20 '13 at 06:36

Adil

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means? please give me example to understand – C Sharper Jul 20 '13 at 06:37
Check my updated answer with an example – Adil Jul 20 '13 at 06:42
my another problem is that, now grid is displayed, two time (may be due to postback), when i add if condition stating if not postback then , bind the grid, its not getting binded single time. how can i overcome this? – C Sharper Jul 20 '13 at 06:52
You can put check if !PostBack or check if your actTab already has it. – Adil Jul 20 '13 at 06:54
but with !postback, grid is not getting binded single time also – C Sharper Jul 20 '13 at 06:56

score 1 · Answer 2 · answered Jul 20 '13 at 06:43

1

useNew keyword to instantiate your gridview

change your code:

Dim gv As GridView

into this code:

Dim gv As New GridView()

Check out this Gridview constructor

Hope this will help you to over come this roadblock.

answered Jul 20 '13 at 06:43

Arun Chandran Chackachattil

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Dynamically bind a grid (object not set to an instance of an object) error

2 Answers2