Populate DropdownList In SelectedIndexChanged DetailsView GridView

In this example i am explaining how to Bind Populate Second DropDownList In SelectedIndexChanged Event Based On Selection Of Other First Dropdown In Detailsview Gridview ASP.NET and save the record in database, in this example i've added two DropDowns in DetailsView control using TemplateField and InsertItemTemplate

The Second DropDown (ddlProducts) is getting populated based on Category selected in Category DropDown , For this i've used SelectedIndexChanged event and findControl method to find the control and sqldataSource is used as datasource for the dropdowns and DetailView


HTML source of the aspx page is

<asp:DetailsView ID="dView" runat="server" AutoGenerateRows="False" 
                 DataSourceID="SqlDataSourceDetails"
                 DefaultMode="Insert" Height="50px" Width="125px">
<Fields>
<asp:TemplateField HeaderText="Category">
<InsertItemTemplate>
<asp:DropDownList ID="ddlCategory" runat="server" AutoPostBack="true"
                  DataSourceID="SqlDataSourceCategory" 
                  DataTextField="Category" DataValueField="Category" 
        OnSelectedIndexChanged="ddlCategory_SelectedIndexChanged" >
</asp:DropDownList>  
<asp:SqlDataSource ID="SqlDataSourceCategory" runat="server" 
ConnectionString="<%$ ConnectionStrings:dvConnectionString %>"
SelectCommand="SELECT DISTINCT [Category] FROM [Products]">
</asp:SqlDataSource>
</InsertItemTemplate>
</asp:TemplateField>

<asp:TemplateField HeaderText="Product">
<InsertItemTemplate>
<asp:DropDownList ID="ddlProducts" runat="server" 
                  DataSourceID="SqlDataSourceProd"
                  DataTextField="Product" DataValueField="Product">
</asp:DropDownList>
<asp:SqlDataSource ID="SqlDataSourceProd" runat="server" 
ConnectionString="<%$ ConnectionStrings:dvConnectionString %>"
SelectCommand="SELECT [Product] FROM [Products] 
WHERE ([Category] = @Category)" 
OnSelecting="SqlDataSourceProd_Selecting">
<SelectParameters>
<asp:Parameter Name="Category" Type="String" />
</SelectParameters>
</asp:SqlDataSource> 
</InsertItemTemplate>
</asp:TemplateField>

<asp:TemplateField HeaderText="Description">
<InsertItemTemplate>
<asp:TextBox runat="server" ID="txtDes" Text='<%#Bind("Des") %>'>
</asp:TextBox>
</InsertItemTemplate>
</asp:TemplateField>
<asp:CommandField ShowInsertButton="True" />
</Fields>
</asp:DetailsView>
        
<asp:SqlDataSource ID="SqlDataSourceDetails" runat="server" 
ConnectionString="<%$ ConnectionStrings:dvConnectionString %>"
SelectCommand="SELECT * FROM [Products]" 
InsertCommand="INSERT INTO Products(Category, Product, Des) 
               VALUES (@Category,@Product,@Des)" 
OnInserting="SqlDataSourceDetails_Inserting" >
<InsertParameters>
<asp:Parameter Name="Category" />
<asp:Parameter Name="Product" />
<asp:Parameter Name="Des" />
</InsertParameters>
</asp:SqlDataSource>

C# code behind

protected void ddlCategory_SelectedIndexChanged
                   (object sender, EventArgs e)
{
 DropDownList ddlProducts = 
     (DropDownList)dView.FindControl("ddlProducts");

        if (ddlProducts != null)
        {
            ddlProducts.DataBind();
        }
}

protected void SqlDataSourceProd_Selecting
    (object sender, SqlDataSourceSelectingEventArgs e)
{
  DropDownList ddlCategory = 
      (DropDownList)dView.FindControl("ddlCategory");

        if (ddlCategory != null)
        {
            e.Command.Parameters["@Category"].Value = ddlCategory.SelectedValue;
        }
}

protected void SqlDataSourceDetails_Inserting
       (object sender, SqlDataSourceCommandEventArgs e)
{
 DropDownList ddlCat = 
         (DropDownList)dView.FindControl("ddlCategory");
 e.Command.Parameters["@Category"].Value = ddlCat.SelectedValue;
 DropDownList ddlProd = 
     (DropDownList)dView.FindControl("ddlProducts");
e.Command.Parameters["@Product"].Value = ddlProd.SelectedValue;
}

VB.NET Code behind

Protected Sub ddlCategory_SelectedIndexChanged
(ByVal sender As Object, ByVal e As EventArgs)

Dim ddlProducts As DropDownList = 
DirectCast(dView.FindControl("ddlProducts"), DropDownList)
    
    If ddlProducts IsNot Nothing Then
        ddlProducts.DataBind()
    End If
End Sub

Protected Sub SqlDataSourceProd_Selecting
(ByVal sender As Object, 
ByVal e As SqlDataSourceSelectingEventArgs)

Dim ddlCategory As DropDownList = 
DirectCast(dView.FindControl("ddlCategory"), DropDownList)
    
    If ddlCategory IsNot Nothing Then
    e.Command.Parameters("@Category").Value = 
                     ddlCategory.SelectedValue
    End If
End Sub

Download the code from here