asp .net dropdownlist selectedindex not working
I have the following piece of code:
DataRow CreateRow(DataTable dt, string name, string country)
{
DataRow dr = dt.NewRow();
dr["Name"] = name;
dr["Country"] = country;
return dr;
}
protected void Page_Load(object sender, EventArgs e)
{
// creating the data table
DataTable dt = new DataTable("Student Details");
// adding two columns Name and Country
dt.Columns.Add("Name", typeof(String));
dt.Columns.Add("Country", typeof(String));
// create 3 rows
dt.Rows.Add(CreateRow(dt, "Varun", "India"));
dt.Rows.Add(CreateRow(dt, "Li", "China"));
dt.Rows.Add(CreateRow(dt, "Yishan", "China"));
// create a data view
DataView dv = new DataView(dt);
DropDownList1.DataSource = dv;
DropDownList1.DataTextField = "Name";
DropDownList1.DataValueField = "Country";
DropDownList1.DataBind();
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
int x = DropDownList1.SelectedIndex;
int temp = 0;
temp++;
}
and the markup looks like this:
<body>
<form id="form1" runat="server">
<div>
<asp:Label ID="Label1" runat="server"></asp:Label>
<br />
<br />
<asp:DropDownList ID="DropDownList1" runat="server"
onselectedindexchanged="DropDownList1_SelectedIndexChanged"
AutoPostBack="true">
</asp:DropDownList>
</div>
</form>
</body>
The problem is that label is always showing Varun no matter what I select. I debugged the code and found out that "DropDownList1.SelectedIndex" is always returning 0 for some reason.
I am not sure why is this happening. The function "DropDownList1_SelectedIndexChanged" is getting called every time I select something from the drop down list.
Thanks
Answer
Looks like you are binding the drop down in the Page_Load...
Remember that when the drop down is changed, it does a post back (AutoPostBack='True'), and since you are binding on Page_Load it will simply rebind ever time the index is changed... not what you want!
you should do something like this:
if (!IsPostBack)
{
BindDropDownList1();
}