In DropDown Selected_Indexchanged event SelectedValue is always getting reset in First Value - asp.net

Question

I have DropdownList which I populate at the time of Page_Load
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DataTable table = new DataTable();
string connectionString = GetConnectionString();
string sqlQuery = "select distinct sname from contacts where sname is not null";
using (OracleConnection conn = new OracleConnection(connectionString))
{
try
{
conn.Open();
using (OracleCommand cmd = new OracleCommand(sqlQuery, conn))
{
using (OracleDataAdapter ODA = new OracleDataAdapter(cmd))
{
ODA.Fill(table);
}
}
}
catch (Exception ex)
{
Response.Write("Not Connected" + ex.ToString());
}
}
//DropDownList1.DataSource = table;
//DropDownList1.DataValueField = "";
DropDownList2.DataSource = table;
DropDownList2.DataValueField = "sname";
DropDownList2.DataTextField = "sname";
DropDownList2.DataBind();
}
}
Now I am trying to populate a GridView when the DropDownList's Item changes
protected void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
{
DataTable table = new DataTable();
string connectionString = GetConnectionString();
string val = DropDownList2.SelectedValue;
string sqlQuery = "SELECT distinct DUTY_DATE FROM DUTY_ROTA,DUTY_TYPES,CONTACTS WHERE DUTY_DATE between SYSDATE and SYSDATE+30 AND DUTY_ROTA.DUTY_TYPE = DUTY_TYPES.DUTY_TYPE AND SNAME IS NOT NULL and contacts.sname = '" + val + "' ORDER BY DUTY_DATE";
using (OracleConnection conn = new OracleConnection(connectionString))
{
try
{
conn.Open();
using (OracleCommand cmd = new OracleCommand(sqlQuery, conn))
{
using (OracleDataAdapter ODA = new OracleDataAdapter(cmd))
{
ODA.Fill(table);
}
}
}
catch (Exception ex)
{
Response.Write("Not Connected" + ex.ToString());
}
}
GridView1.DataSource = table;
GridView1.DataBind();
}
I have enabled the AutoPostBack. Now when I am changing a DropDownList item to a different one the Page is loading but always retaining the first value. I tried to debug , I found that
string val = DropDownList2.SelectedValue;
the val variable is always the first value that is returned by the Query. Can anybody please tell me how could I get rid of this. I want to populate the GridView whenever I am selecting any item in the dropdown.

Answer 1

Hi i think that dropdownlist charge again when you select other item. Put a Break Point in Page Load and look if your dropdownlist charge again i don't see other reason. Good Luck

Answer 2

Your Drop downlist should look like as following :
<asp:DropDownList ID="DropDownList2" runat="server" AutoPostBack="True"
OnSelectedIndexChanged="DropDownList2_SelectedIndexChanged">
</asp:DropDownList>
Make sure AutoPostBack is Set to TRUE.
One more thing you can try is to select the item when the index is greater than -1.
if(DropDownList2.SelectedIndex != -1)
{
string val = DropDownList2.SelectedItem.Value;
// enter code here
}