Getting value from DropDownList

[E11esar]

Hi there.

I have created a DropDownList in asp.net with declaration in the aspx file as follows:

<asp:DropDownList ID="lbExtractType" runat="server">
  <asp:ListItem Value=" "></asp:ListItem>
  <asp:ListItem Value="apple">apple</asp:ListItem>
  <asp:ListItem Value="banana">banana</asp:ListItem>
  <asp:ListItem Value="orange">orange</asp:ListItem>
  <asp:ListItem Value="peach">peach</asp:ListItem>
  <asp:ListItem Value="pear">pear</asp:ListItem>
  <asp:ListItem Value="grape">grape</asp:ListItem>
</asp:DropDownList>
 

I am then (as a test) trying to display this value as follows in the cs file:

DropDownList list = (DropDownList)Master.FindControl("ContentPlaceHolder1").FindControl("lbExtractType");
        string extractType = list.SelectedItem.Value;
        MessageBox.Show("Extract Type = " + extractType);
 

When I run this I get the error message:

 
 Server Error in '/WebSite1' Application. 
 
 Object reference not set to an instance of an object. 
 
Line 161:
Line 162:        DropDownList list = (DropDownList)Master.FindControl("ContentPlaceHolder1").FindControl("lbExtractType");
Line 163:        string extractType = list.SelectedItem.Value;
Line 164:
Line 165:        MessageBox.Show("Extract Type = " + extractType);
 
 Source File: c:\00 CADLine Projects\AJAX\WebSite1\Default.aspx.cs    Line: 163 
 
 

Now I would expect this if I hadn't initialised everything correctly but I "think" I have done this right..!

Any help will be greatly appreciated please?

Thank you.

M :)

[Bassem]

@E11esar
Hi E11esar,
What is Master? Is it a master page? I don't think you can access master page controls, you have to use content page first. It may be what make the object reference set to null. If I'm wrong, I'm glad to know.
Kind Regards,
Bassem

[E11esar]

Hi there.

Yes it is within a Master page, hence why I am using the

DropDownList list = (DropDownList)Master.FindControl("ContentPlaceHolder1").FindControl("lbExtractType"); 
 

to find the control. That part I am happy with as I know that does work but there is something strange going on here.

Ofcourse the issue might be caused by me using an AJAX Accordion control, so the DropDownList is within the Content of the AccordionPane..?

I have also tried a statement such as

DropDownList list = (DropDownList)Master.FindControl("ContentPlaceHolder1").FindControl("Accordion1").FindControl("AccordionPane1").FindControl("lbExtractType");
 

so this may give an indication of what I am trying to do.

Thank you.

Mark :)

[E11esar]

Hi there.

I've just solved this one: I hadn't used enough FindControl() commands to get down to the layer that the target control was within.

All sorted now.

Thank you.

M :)