如何获取网格视图内的下拉列表中的值？答案

【问题标题】：how to get values in dropdownlist bounded within a gridview?如何获取网格视图内的下拉列表中的值？
【发布时间】：2013-12-01 17:12:25
【问题描述】：

在gridview里面有一个下拉列表

<asp:TemplateField HeaderText="Quantity">
    <ItemTemplate>
        <asp:DropDownList ID="quantity" runat="server" DataValueField="ItemID" DataTextField="Quantity">
        </asp:DropDownList>
    </ItemTemplate>
</asp:TemplateField>

对于每个 itemid，Database Table 的 Quantity 字段中都有一些数值我希望此下拉列表必须包含购物车中所有商品的值 from 1 to quantity.DataTextField

gridview绑定的过程是

create proc [dbo].[prcItemsinCart](@CartID int)
as
    select distinct ct.Price,ct.Quantity,ct.ItemID,
           ct.CartID,ct.ProductID,p.ProductName,
           isnull((  select top 1 convert(varchar,PhotoID,10) + '.' + ExtName
                 from ProductPhoto 
                 where ProductID = ct.ProductID ),'NoImage.jpg'
           ) as Product, 
           ( Select Price*Quantity 
             from CartItems 
             where CartID=ct.CartID and ProductID=ct.ProductID
           ) as SubTotal
    from CartItems as ct 
    inner join ProductInfo as p on ct.ProductID=p.ProductID 
    inner join ProductPhoto as pp on ct.ProductID=pp.ProductID 
    where ct.CartID=@CartID

【问题讨论】：

标签： c# asp.net gridview data-binding drop-down-menu

【解决方案1】：

我会在TemplateField 中添加一个HiddenField 来保存 CartID，我将在代码中使用 CartID。我的标记应如下所示：

<asp:TemplateField HeaderText="Quantity">
    <ItemTemplate>  
        <asp:HiddenField ID="hdnId" runat="server" value='<%#Eval("CartID") %>'></asp:HiddenField>                            
        <asp:DropDownList ID="quantity" runat="server" DataValueField="ItemID" DataTextField="Quantity">
        </asp:DropDownList>
    </ItemTemplate>
</asp:TemplateField>

在代码中，在 GridView 的 RowDataBound 中，我找到了 DropDownList 和 HiddenField，运行 Sql Query 以获取我预期的数据，并将它们绑定到我的 DropdownList：

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        DropDownList quantity = e.Row.FindControl("quantity") as DropDownList;
        HiddenField hdnId = e.Row.FindControl("hdnId") as HiddenField;

        if (quantity != null && hdnId != null)
        {
            string queryString = String.Format("SELECT ItemID, Quantity FROM  CartItems  WHERE CartID= {0}", hdnId.Value);

            //MyConnectionString is your connection string in web.config
            using (SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["MyConnectionString"].ToString()))
            {
                SqlCommand command = new SqlCommand(queryString, connection);
                connection.Open();
                SqlDataReader reader = command.ExecuteReader();
                quantity.DataSource = reader;
                quantity.DataValueField = "ItemID";
                quantity.DataTextField = "Quantity";
                quantity.DataBind();               
            }
        }        

    }
}

【讨论】：