Select / Deselect all checkbox in gridview in VB.NET

We can select and deselect checkbox in gridview in onPostback event of checkbox in gridview header.

Protected Sub CheckBox2_CheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs)
Dim gv As GridViewRow

Dim chkH As CheckBox = CType(GridView1.HeaderRow.FindControl("CheckBox2"), CheckBox)

If chkH.Checked = True Then
For Each gv In GridView1.Rows

Dim chk As CheckBox = CType(GridView1.Rows(gv.RowIndex).FindControl("CheckBox1"), CheckBox)
chk.Checked = True
Next
Else
For Each gv In GridView1.Rows

Dim chk As CheckBox = CType(GridView1.Rows(gv.RowIndex).FindControl("CheckBox1"), CheckBox)
chk.Checked = False
Next

End If
End Sub

Here is the sample image output.