We help IT Professionals succeed at work.
Get Started

can't get asp.net ListBox SelectedValue

SweatCoder asked
Last Modified: 2012-05-11
No matter what I try, I can't get the SelectedValue from my listbox on postback. I have triple-checked and even verified by stepping through code that I'm not rebinding my listbox to the datasource on postback (button click).

listbox declaration:
<asp:ListBox ID="listAvailableAMCs" Rows="8" Width="300px" DataValueField="ID" DataTextField="Company" runat="server"></asp:ListBox>

Listbox data population works fine.

A button click calls this:

protected void LinkAMC(object sender, EventArgs e)
        if(listAvailableAMCs.SelectedValue != string.Empty)


SelectedValue is always blank. SelectedText is blank and SelectedIndex is -1.

A view source reveals this html:

<select size="8" name="ctl00$MasterMain$listAvailableAMCs" id="MasterMain_listAvailableAMCs" style="width:300px;">
      <option value="19">Como AMC</option>
      <option value="21">Sinatra AMC</option>
      <option value="20">Martin AMC</option>

Those option values and text values are exactly right.

What am I missing?
Watch Question
Top Expert 2010
This problem has been solved!
Unlock 3 Answers and 7 Comments.
See Answers
Why Experts Exchange?

Experts Exchange always has the answer, or at the least points me in the correct direction! It is like having another employee that is extremely experienced.

Jim Murphy
Programmer at Smart IT Solutions

When asked, what has been your best career decision?

Deciding to stick with EE.

Mohamed Asif
Technical Department Head

Being involved with EE helped me to grow personally and professionally.

Carl Webster
CTP, Sr Infrastructure Consultant
Ask ANY Question

Connect with Certified Experts to gain insight and support on specific technology challenges including:

  • Troubleshooting
  • Research
  • Professional Opinions
Did You Know?

We've partnered with two important charities to provide clean water and computer science education to those who need it most. READ MORE