Changing a column in multiple DataGrid rows using checkboxes

Introduction

This article will demonstrate how to change the value of a DataGrid column in multiple rows using checkboxes. This is a very common problem and it's easily implementable, so without much ado, let's get to the point.

Before I start, though, I'll put forward one assumption I make in this article, make sure your code meets the underlying requirement, otherwise you'll have to do some extra work.

I'll assume that the data bound to the grid is also editable through some object in your code (in other words, DataGrid columns are properties of one object) and you have an update routine for this object. For example, in our case, the object we're using is PurchaseOrder, and the column (property) is ApprovalStatus.

First off, let's start with a simple bind routine. The getApproverPOs function simply returns a DataTable object, you can replace it with your own DataTable.

Sub BindGrid()
    dgPO.DataSource = PurchaseOrder.getApproverPOs
    dgPO.DataBind()
End Sub

In our example, we have a dropdown named lstStatus and a button named btnApply.

The Iterate routine which follows next will loop through each row and see if the checkbox (named chk) in the DataGrid's first template column is checked, if so, it will load PurchaseOrder, set a new ApprovalStatus, and update the changes.

Public Sub Iterate() 
 Dim DGItem As DataGridItem
 Dim chkSel As System.Web.UI.WebControls.CheckBox
 Dim po As PurchaseOrder
 For Each DGItem In dgPO.Items
  chkSel = DGItem.FindControl("chk")
  If chkSel.Checked Then
    po = PurchaseOrder.getPO(DGItem.Cells(1).Text) 'pass the po number to get
    po.ApprovalStatus = lstStatus.SelectedItem.Value
    'send an email to original PO poster
    PurchaseOrder.NotifyPoster(po)
    po.Update()
  End If
 Next
End Sub

And finally, we need an event handler for our button which will point to the Sub above. We use Response.Redirect in the end to refresh the checkboxes, as well as the ApprovalStatus column.

Private Sub btnApply_Click(ByVal sender _
  As System.Object, ByVal e As System.EventArgs) _
  Handles btnApply.Click
    Iterate()
    Response.Redirect("thissamefile.aspx")
End Sub

That's all there is! Hope this was helpful.

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