DropDownList selection is not reflected in server side
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I have a dropdownlist in my asp.net web page. Its a server side control. I am doing a ajax call and inside the ajax call I am adding a new item to the ddl and setting it as selected. It is showing nicely on page. But when I do a post back the selected item gives me the old selected item in the dropdownlist.

    // ddlCaseNumber is the id of the dropdownlist and its clientid property is set
    // to static.
    // Removes the selected attribute of selected selected item .
    $('#ddlCaseNumber option:selected').removeAttr("selected");
    
    // Add the new item to dropdownlist.
    $('#ddlCaseNumber').append('<option selected="selected" value=' + crmid + '>' 
                               + crmid + '</option>');
    
    // Code behind code to get the new value.
    // This line is giving the old value instead of giving new value.
    string strNewValue = ddlCaseNumber.SelectedItem.Value;


Can anyone please tell me how to get the new item added in code behind?


Thanks in advance.