asked on 4/8/2013

Object reference not set... asp 4

The list box in question is:

<asp:ListBox ID="lstEducation" runat="server" Width="205px">
                        <asp:ListItem >High School</asp:ListItem>
                        <asp:ListItem>Associate&#39;s Degree</asp:ListItem>
                        <asp:ListItem>Four-Year College</asp:ListItem>
                        <asp:ListItem>Masters</asp:ListItem>
                        <asp:ListItem>PhD</asp:ListItem>
                    </asp:ListBox>

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This error occurs in page load at:

lstEducation.SelectedItem.Text = Session("education")

The intelesens shows a valid choice for the session variable.
-------------------

Object reference not set to an instance of an object.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error: 


Line 62:             ddlMaterialStatus.SelectedItem.Text = Session("maritalStatus")
Line 63: 
Line 64:             lstEducation.SelectedItem.Text = Session("education")
Line 65:             chkAddComment.Checked = Session("addComment")
Line 66:             txtComment.Text = Session("comment")

Stack Trace: 

[NullReferenceException: Object reference not set to an instance of an object.]
   addContact.Page_Load(Object sender, EventArgs e) in ... AddContact.aspx.vb:64
   System.Web.UI.Control.OnLoad(EventArgs e) +91
   System.Web.UI.Control.LoadRecursive() +74
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2207

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.272

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ASP.NET .NET Programming Visual Basic.NET

Last Comment

Mike Eghtebas

4/8/2013

Ioannis Paraskevopoulos

4/8/2013

Hi,

Try moving your code in Page_LoadComplete. This ensures that the controls have been loaded.

Giannis

Mike Eghtebas

4/8/2013

ASKER

I was trying to do validation in client side. OnLoad will require postback.

Ioannis Paraskevopoulos

4/8/2013

Well, it hits on Page_Load, so this doesn't seem to be in client side.

ASKER CERTIFIED SOLUTION

Nasir Razzaq

4/8/2013

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Mike Eghtebas

4/8/2013

ASKER

Hi CodeCruiser,

This sort of masks the problem there is in my solution. After returning from Confirm page AddNew page. In the load event of AddNew page I have:

lstEducation.SelectedItem.Text = Session("education")

The session variable has some value in it but it doesn't deliver to lstEducation control.

Why lstEducation.SelectedItem.Text = Session("education") is not working?

Thank you

Mike Eghtebas

4/8/2013

ASKER

It works only if Selected="True" attribute is added:

  <asp:ListBox ID="lstEducation" runat="server" Width="205px">
                        <asp:ListItem Selected="True">High School</asp:ListItem>
                        <asp:ListItem>Associate&#39;s Degree</asp:ListItem>
                        <asp:ListItem>Four-Year College</asp:ListItem>
                        <asp:ListItem>Masters</asp:ListItem>
                        <asp:ListItem>PhD</asp:ListItem>
           </asp:ListBox>

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Why it doesn't work with no Selected="True" in one of the items?

Nasir Razzaq

4/8/2013

Try

lstEducation.SelectedItem = Session("education")

Mike Eghtebas

4/8/2013

ASKER

Error 10 Property 'SelectedItem' is 'ReadOnly'.

I am getting this error.

I possibly need to cycle through the values and find index of some sort and then use the index value to select it.

Mike Eghtebas

4/8/2013

ASKER

lstEducation.SelectedValue = Session("education")

works ok.

Thanks.