Enabling a disabled button in datagrid footer

[vedicman]

I have a button (btnADD)in the footer of a datagrid for adding new rows to the grid. Initially I am setting the enabled property to false, then I want to enable the button when data is entered into a specific textbox (also in the footer). I'm using the ontextchanged event to run:

Sub EnableAddButton(sender As Object, e As System.EventArgs)

'Dim btnAdd as button = e.Item.FindControl("btnAdd")
Dim btnAdd as button=CType(FindControl("btnAdd"), button)
btnAdd.enabled="true"

End Sub

I'm getting the following error:
Object reference not set to an instance of an object.

Obviously I don't have this wired up properly and I'm looking for guidance. I think I'm not using the correct parameters in the sub. I've tried others, but I haven't hit upon the right one. I've also dimmed btnAdd as shown with the line that is commented out. It gives the same error.

Thanks....Franco

 

[DotNetGnat]

you should do this in the itemdatabound event of the datacontrol...

-DNG

 

[DotNetGnat]

oops...i meant to say...

you should do this in the itemdatabound event of the datagrid]/b]...

-DNG

 

[vedicman]

Can you provide some details?

I wired the OnItemDatabound method of the datagrid to the sub below:

Sub EnableAddButton(sender As Object, e As System.Web.UI.WebControls.DataGridItemEventArgs)

Dim btnAdd as button = e.Item.FindControl("btnAdd")
btnAdd.enabled="true"

End Sub

I'm getting this error: Object reference not set to an instance of an object on this line:

btnAdd.enabled="true"

Obviously, I'm still not understanding the concept!

 

[ca8msm]

That's probably because the button won't exist on every row - make sure you are only checking on item or alternating item rows.


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[jbenson001]

Add this IF to your event:

If e.Item.ItemType = ListItemType.Footer Then
...Your code
End If

 

[DotNetGnat]

something like this:

Private Sub yourdatagrid_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DataGridItemEventArgs) Handles yourgrid.ItemDataBound
If e.item.itemtype = ListItemType.Footer then
Dim btnAdd as button = e.Item.FindControl("btnAdd")
btnAdd.enabled="true"

End Sub

-DNG

 

[ca8msm]

Oops, I just saw that the button was in the footer - try using jbenson001's example instead.


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Try the Search Facility or read FAQ222-2244 on how to get better results.

 

[vedicman]

jbenson001

With the following code, the button(btnAdd) is loading disabled, but when I enter data into the textbox(txtWeek) it is not becomming enabled. I'm still missing something. Any other ideas?

Sub EnableAddButton(sender As Object, e As System.Web.UI.WebControls.DataGridItemEventArgs)

If e.Item.ItemType = ListItemType.Footer Then
Dim txtWeek as textbox = e.Item.FindControl("txtWeek")
If txtWeek.text <> "" Then
Dim btnAdd as button = e.Item.FindControl("btnAdd")
btnAdd.enabled="true"
End If
End If

End Sub

 

[ca8msm]

It won't be enabled unless you tell it to (at the minute you are checking the text when the footer is bound to the grid, but not once the text changes).


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[vedicman]

ca8msm

We've come full circle...how do I enable the button when txtWeek changes? See my initial post.

Thanks...Franco

 

[jbenson001]

You need javascript to do that.