How can I retrieve data from sql database by selecting an item from a drop down list and displaying the selected item information in a data grid view?
following is a code that I have but its not working I can select from a dropdown list but nothing appears in a data grid view
ASP.NET Code:
<
table>
       
<tr>
            
<td>
                
<asp:Label ID="lblShow" runat="server" Text="Select Station ID"></asp:Label>
                
<asp:DropDownList ID="ddlshow" runat="server" DataSourceID="SqlDataSource3" 
                    
DataTextField="Perway_Status" DataValueField="Perway_Status" 
                    
onselectedindexchanged="ddlshow_SelectedIndexChanged">
                    
<asp:ListItem Text="All" Value="All" Selected="True"/>
                
</asp:DropDownList>
                
<asp:SqlDataSource ID="SqlDataSource3" runat="server" 
                    
ConnectionString="<%$ ConnectionStrings:StatStressConnectionString %>" 
                    
                    
SelectCommand="SELECT DISTINCT Stations.Station_ID, Stations.Station_Name, Sections.Section_ID, Sections.Perway_Status, Sections.Equipment_Status, Station_Status_Current.Status_Time FROM Sections INNER JOIN Stations ON Sections.Section_ID = Stations.Section_ID CROSS JOIN Station_Status_Current CROSS JOIN Status_Legend ORDER BY Stations.Station_ID">
                
</asp:SqlDataSource>
            
</td>
           
       
</tr>
       
<tr>
            
<td>
                
<asp:GridView ID="GdvshowAll" runat="server" DataSourceID="SqlDataSource1" 
                    
AutoGenerateColumns="False">
                    
<Columns>
                        
<asp:BoundField DataField="Section_Name" HeaderText="Section_Name" 
                            
SortExpression="Section_Name" />
                        
<asp:BoundField DataField="Perway_Status" HeaderText="Perway_Status" 
                            
SortExpression="Perway_Status" />
                        
<asp:BoundField DataField="Equipment_Status" HeaderText="Equipment_Status" 
                            
SortExpression="Equipment_Status" />
                        
<asp:BoundField DataField="Station_ID" HeaderText="Station_ID" 
                            
SortExpression="Station_ID" InsertVisible="False" ReadOnly="True" />
                        
<asp:BoundField DataField="Station_Lines" HeaderText="Station_Lines" 
                            
SortExpression="Station_Lines" />
                        
<asp:BoundField DataField="Status_Time" HeaderText="Status_Time" 
                            
SortExpression="Status_Time" />
                        
<asp:BoundField DataField="Station_Name" HeaderText="Station_Name" 
                            
SortExpression="Station_Name" />
                    
</Columns>
                
</asp:GridView>
                
<asp:SqlDataSource ID="SqlDataSource1" runat="server" 
                    
ConnectionString="<%$ ConnectionStrings:StatStressConnectionString %>" SelectCommand=" SELECT DISTINCT 
                         Sections.Section_Name, Sections.Perway_Status, Sections.Equipment_Status, Stations.Station_ID, Stations.Station_Lines, 
                         Station_Status_Current.Status_Time, Stations.Station_Name
FROM            Sections LEFT OUTER JOIN
                         Stations ON Stations.Section_ID = Sections.Section_ID LEFT OUTER JOIN
                         Station_Status_Current ON Station_Status_Current.Station_ID = Stations.Station_ID AND Station_Status_Current.Station_ID = Stations.Section_ID
WHERE        (Stations.Station_ID = @ddlshow)
ORDER BY Stations.Station_ID ">
                    
<SelectParameters>
                        
<asp:ControlParameter ControlID="ddlshow" Name="ddlShow" 
                            
PropertyName="SelectedValue" />
</SelectParameters>
</asp:SqlDataSource>
</td>
</tr>
</
table> 
C# Code:
protected
 void ddlshow_SelectedIndexChanged(object sender, EventArgs e)
        {
            SqlDataSource1.DataBind();
            GdvshowAll.DataBind();
        }
        
public override void VerifyRenderingInServerForm(Control control)
        {
            
return;
        }