下拉选定的值以在 gridview 中绑定 DropDown 下一行

Question

我在一个动态的网格视图中有一个下拉菜单。我想要的是从第一行的下拉列表中选择第一个值后，使用第一行中的选定值绑定第二行中的下拉列表。

                                        <asp:TemplateField HeaderText="Staff">
                                        <ItemTemplate>
                                            <asp:DropDownList ID="ddlInsentiveCategory" runat="server" OnSelectedIndexChanged="ddlInsentiveCategory_SelectedIndexChanged" AutoPostBack="true" DataSourceID="InsentiveDataSource"
                                                DataTextField="Name" DataValueField="SalesStaffID">
                                            </asp:DropDownList>
                                            <asp:RequiredFieldValidator ID="RequiredFieldValidator70" runat="server" ControlToValidate="ddlInsentiveCategory" 
                                                CssClass="rfv" ErrorMessage="*" ForeColor="Red" InitialValue="0" ValidationGroup="group2"></asp:RequiredFieldValidator>
                                            <asp:SqlDataSource ID="InsentiveDataSource" runat="server" ConnectionString="<%$ ConnectionStrings:Connection %>"
                                                SelectCommand="SELECT '--Select--' as [Name],'0' as [SalesStaffID]  union all SELECT [Name],[SalesStaffID] FROM [SalesStaff] WHERE ([StaffCategoryID] = @StaffCategoryID)">
                                                <SelectParameters>
                                                    <asp:ControlParameter ControlID="hdnInsentiveCategoryID" Name="StaffCategoryID" PropertyName="Value"
                                                        Type="Int32" />
                                                </SelectParameters>
                                            </asp:SqlDataSource>
                                            <asp:HiddenField ID="hdnInsentiveCategoryID" runat="server" Value='<%# Bind("StaffCategoryID") %>' />
                                        </ItemTemplate>
                                    </asp:TemplateField>

帮助我实现这一目标。提前致谢。

Answer 1

我假设您的 gridview 也在使用 SqlDataSource，否则将需要在提到的方法中进行一些小的更改。

• 您需要将Selecting 事件添加到 SqlDataSource 以获取下拉列表 如下面的标记。

  <asp:SqlDataSource ID="InsentiveDataSource" runat="server" 
             OnSelecting="InsentiveDataSource_Selecting" ....
  

• 在后面的代码中添加以下 C# 代码。正在订阅下拉列表的 SqlDataSource 的 Selecting 事件，因为它允许在获取数据之前对 SqlDataSource 进行更改。

  • 在这里，您正在获取下拉列表的选定值，其索引具有 刚刚被更改，然后获取下一行下拉控件。

  • 一旦获得下一行下拉控件，我们就简单地调用它 DataBind 方法将触发其数据的 Selecting 事件 来源

  • 在选择事件中，我们可以将参数值动态设置为上一行的下拉选择值。

    private int dropdpownValue;
    
    protected void ddlInsentiveCategory_SelectedIndexChanged ( object sender, EventArgs e) 
    {
    
     //get selected value of drop down and then find
     //the row index of this drop down control
    
     DropDownList ddl = sender as DropDownList;
     int.TryParse( (sender as DropDownList).SelectedItem.Value, out ddlValue);
     GridViewRow row = (GridViewRow) ddl.NamingContainer;
     int ddlRowIndex = row.RowIndex;
    
     //find the next row dropdownlist and if there is a next row,
     //then get this control and databind it
    
     GridView gridView =   (GridView)ddl.NamingContainer.NamingContainer ;
     if((ddlRowIndex + 1) <= (gridView.Rows.Count -1)) {
         DropDownList nextRowDDL = ((System.Web.UI.WebControls.GridView)ddl.NamingContainer.NamingContainer ).Rows[ ddlRowIndex + 1].FindControl("ddlInsentiveCategory")
         nextRowDDL.DataBind();
       }
    }
    
    protected void InsentiveDataSource_Selecting(object sender, SqlDataSourceSelectingEventArgs e)
    {
       if(dropdpownValue> 0) {
              e.Command.Parameters[0].Value=  dropdpownValue;
              dropdownValue = 0;
       }
    }
    

Answer 2

我能够通过使用 SelectedIndexChanged 事件来解决这个问题。代码如下。希望这会有所帮助。

        protected void ddlInsentiveCategory_SelectedIndexChanged(object sender, EventArgs e)
    {

        DropDownList ddlMainCategory = (DropDownList)gvInsentivePayment.Rows[0].FindControl("ddlInsentiveCategory");
        DropDownList ddlDependentCategory = (DropDownList)gvInsentivePayment.Rows[1].FindControl("ddlInsentiveCategory");

        if (ddlDependentCategory.SelectedIndex == 0)
        {

            ddlMainCategoryValue = Convert.ToInt32(ddlMainCategory.SelectedValue);


            List<SalesStaff> FetchDependentList = // Bind the list using selected value from the 1st dropdown in the first row.


            ddlDependentCategory.DataSourceID = null; //Assigning null to remove the DatasourceID in client side.
            ddlDependentCategory.DataSource = FetchDependentList;
            ddlDependentCategory.DataTextField = "Name";
            ddlDependentCategory.DataValueField = "ID";
            ddlDependentCategory.DataBind();
        }

    }