Learn how to build an E-Commerce site with Angular 5, a JavaScript framework used by developers to build web, desktop, and mobile applications.
can't get asp.net ListBox SelectedValue
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:ListB
Listbox data population works fine.
A button click calls this:
protected void LinkAMC(object sender, EventArgs e)
{
if(listAvailableAMCs.Selec
Utilities.LinkAMC(int.Pars
LoadGridData();
}
SelectedValue is always blank. SelectedText is blank and SelectedIndex is -1.
A view source reveals this html:
<select size="8" name="ctl00$MasterMain$lis
<option value="19">Como AMC</option>
<option value="21">Sinatra AMC</option>
<option value="20">Martin AMC</option>
</select>
Those option values and text values are exactly right.
What am I missing?
listbox declaration:
<asp:ListBox ID="listAvailableAMCs" Rows="8" Width="300px" DataValueField="ID" DataTextField="Company" runat="server"></asp:ListB
Listbox data population works fine.
A button click calls this:
protected void LinkAMC(object sender, EventArgs e)
{
if(listAvailableAMCs.Selec
Utilities.LinkAMC(int.Pars
LoadGridData();
}
SelectedValue is always blank. SelectedText is blank and SelectedIndex is -1.
A view source reveals this html:
<select size="8" name="ctl00$MasterMain$lis
<option value="19">Como AMC</option>
<option value="21">Sinatra AMC</option>
<option value="20">Martin AMC</option>
</select>
Those option values and text values are exactly right.
What am I missing?
Do more with
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
The code seems to be fine, Check the following points:
1. You are not reloading the listbox after each postback
2. Make sure that you do not have ViewStateEnabled="false" for a parent container
3. You are rebinding the ListBox each time, instead of not IsPostback
1. You are not reloading the listbox after each postback
2. Make sure that you do not have ViewStateEnabled="false" for a parent container
3. You are rebinding the ListBox each time, instead of not IsPostback
1 is good, as mentioned in original post.
2 - viewstate is disabled for the whole site because I don't need. Maybe you've got a point here, but I use asp:DropDownList on other pages and it works fine with viewstate turned off. Why would ListBox be different from ddl in that respect?
3- Not sure exactly what you mean. If i'm not in a postback, that's when I bind the listbox.
2 - viewstate is disabled for the whole site because I don't need. Maybe you've got a point here, but I use asp:DropDownList on other pages and it works fine with viewstate turned off. Why would ListBox be different from ddl in that respect?
3- Not sure exactly what you mean. If i'm not in a postback, that's when I bind the listbox.
Please post your Page_Load Event Code.. I think You are Missing the IsPostBack checking in the load event.. I need to modify your Page_Load event so that you get ur SelectedValue right when you click the button..
I am only binding data source when not in a postback:
if (!IsPostBack)
{
listAvailableAMCs.DataSour
listAvailableAMCs.DataBind
}
I have noticed that everything works fine when I use a declarative data source in the aspx, but this becomes awkward. I'd rather get my data from a class library where I can do some logic checks, pass in variables, parameterize the query, etc.
if (!IsPostBack)
{
listAvailableAMCs.DataSour
listAvailableAMCs.DataBind
}
I have noticed that everything works fine when I use a declarative data source in the aspx, but this becomes awkward. I'd rather get my data from a class library where I can do some logic checks, pass in variables, parameterize the query, etc.
Premium Content
You need an Expert Office subscription to comment.Start Free Trial