编译器错误消息：CS0103：当前上下文中不存在名称“ listBox1”

Question

I am getting the above error. The error is on line 33, it says.

Here's the code:

Source Error:

Line 31: 
Line 32: while(r.Read()) {
Line 33:     listBox1.Items.Add(new ListItem(r["first_name"], r["first_name"])); //this is the offending line
Line 34: }
Line 35: con.Close();

Now, I figured my ASP.NET was fine, I have the following code there:

<asp:ListBox ID="listBox1" runat="server">
</asp:ListBox>

What might I be doing incorrectly here? I have the user control setup in the .aspx file, I have the correct item in my .aspx.cs file - it should work, shouldn't it? What am I missing? I'm still new to C#

Answer 1

If you have created a UserControl instance inside your aspx then you have to find the ListBox control inside the UserControl instance using its Controls collection.

Here's a link on MSDN.

Another alternative is to have your individual control handlers inside the code-behind file of the UserControl .

Answer 2

Does your listBox1 control exist inside your designer.cs file? If not, regenerate the auto-generated C# file by deleting it, right clicking the aspx file and clicking on "Convert to Web Application".