如何在C＃代码中存储RadComboBox选择的值？

Question

My RadComboBox is supposed to drop down and display options for me to select. the options are name but the selected values are numbers corresponding to the ID of the center.

 <telerik:RadComboBox DataValueField="OPERATION_CENTER_ID" RenderingMode="Full" EmptyMessage="Select Operation Center" DataTextField="OPERATION_CENTER_NAME" ID="RadComboBox1" runat="server"></telerik:RadComboBox> 

  protected void rdOrders_NeedDataSource(object sender, Telerik.Web.UI.GridNeedDataSourceEventArgs e) { //Get OPERATION_CENTER_ID in f1 from f2 query (it is an int) string f2 = "select * from [dbo].[GetOperationCentersInfo]('F')"; SQLHelper a = new SQLHelper(SQLHelper.ConnectionStrings.EmallShippingConnectionString); int ID = RadComboBox1.SelectedValue; { string f1 = "select * from [dbo].[GetReadyDeliveryOrderItems](" + ID + ")"; DataTable DataTable1 = a.getQueryResult(f1); //Orders Query by OPERATION_CENTER_ID DataTable DataTable2 = a.getQueryResult(f2); //Operation centers Query DataTable testDataTable = new DataTable(); rdOrders.DataSource = DataTable1; RadComboBox1.DataSource = DataTable2; RadComboBox1.DataBind(); } 

Basically when the user selects a value from RadComboBox1 , I want to store that value in an int variable.

Answer 1

Hope that DataValueField is assigned while binding the grid, and the Value is convertible to an integer. Then I would like to suggest int.TryParse for this conversion, So that you use its return value to check whether the conversion is successful or not. See the code below:

int ID;
if(Int32.TryParse(RadComboBox1.SelectedValue,out ID))
{
  // You can proceed with ID 
}
else
{
  // Conversion failed
}

Answer 2

Is there any particular reason that you have to data-bind your RadComboBox control in a NeedDataSource event? This will not guarantee that your RadComboBox control will be loaded correctly due to the life cycle of your page/control.

What you possibly can do is to add your data-binding code to Page_Load event, something like below.

protected void Page_Load(object sender, EventArgs e)
{
   if (!IsPostBack)
   {
      BindRadComboBox();
   }
}

private void BindRadComboBox()
{
    string f2 = "select * from [dbo].[GetOperationCentersInfo]('F')";

     SQLHelper a = new SQLHelper(SQLHelper.ConnectionStrings.EmallShippingConnectionString);

       int ID = RadComboBox1.SelectedValue; {
       string f1 = "select * from [dbo].[GetReadyDeliveryOrderItems](" + ID + ")";
       DataTable DataTable1 = a.getQueryResult(f1); //Orders Query by OPERATION_CENTER_ID
       DataTable DataTable2 = a.getQueryResult(f2); //Operation centers Query
       DataTable testDataTable = new DataTable();
       rdOrders.DataSource = DataTable1;
       RadComboBox1.DataSource = DataTable2;
       RadComboBox1.DataBind();
}

You will need to double check the code that fetches the data though. Also for converting string to integer, please refer to un-lucky's answer, which is recommended way of doing it.

Hope this helps.