Question

The Scenario which i have thought and which i want to do is that I have 2 combo boxes.. One of Country and One of Cities.. On Page Load, Country Combo box must be filled with the corresponding values present in the Database and at that time My Cities Combo box should be hidden.. By selecting the Country from the Filled Country Combo Box, the hidden Combo Box that is the Cities Combo Box visible to true and filled with those cities that the user selected the country from the country combo box…

Can any one help me with that?

Answer 1

Here is a sample that uses SqlDataSource. You will have to adjust the datasource and the select command accordingly.

<asp:DropDownList ID="ddlCountry" runat="server" AppendDataBoundItems="True" 
            AutoPostBack="True" DataSourceID="SqlDataSource1" DataTextField="Country" 
            DataValueField="Country">
        <asp:ListItem Text="Select a Country" Value="-1"></asp:ListItem>
        </asp:DropDownList>
        <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
            ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>" 
            SelectCommand="SELECT DISTINCT [Country] FROM [Customers]"></asp:SqlDataSource>
        <asp:DropDownList ID="ddlCities" runat="server" AppendDataBoundItems="True" 
            DataSourceID="SqlDataSource2" DataTextField="City" DataValueField="City">
        <asp:ListItem Text="Select a City" Value="-1"></asp:ListItem>
        </asp:DropDownList>
        <asp:SqlDataSource ID="SqlDataSource2" runat="server" 
            ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>" 
            SelectCommand="SELECT DISTINCT [City] FROM [Customers] WHERE ([Country] = @Country)">
            <SelectParameters>
                <asp:ControlParameter ControlID="ddlCountry" Name="Country" 
                    PropertyName="SelectedValue" Type="String" />
            </SelectParameters>
        </asp:SqlDataSource>