Question

我的数据库中有两个表如下：

建议表：ID，标题，描述，StatusID等等

SuggestionsStatus表：ID，状态

我正在使用GridView来显示建议，在最后一栏中我放了一个DropDownList来选择每个Suggestion的状态。现在，当我试图在DropDownList中显示状态时，我收到以下错误，我不知道原因：

非静态字段，方法或者需要对象引用 property'System.Web.UI.WebControls.ListControl.Items.get'

我的ASP.NET代码：

<asp:GridView ID="GridView1" runat="server" AllowPaging="True" 
                        AllowSorting="True" AutoGenerateColumns="False" DataKeyNames="ID" 
                        width="950px" CssClass="mGrid"
                        AlternatingRowStyle-CssClass="alt" 
                        RowStyle-HorizontalAlign="Center" 
                        DataSourceID="SqlDataSource1" 
                        OnRowDataBound="GridView1_RowDataBound" >
            <AlternatingRowStyle BackColor="White" ForeColor="#284775" />
            <HeaderStyle Font-Bold = "true" ForeColor="Black" Height="20px"/> 
            <Columns>
                <asp:BoundField DataField="ID" HeaderText="ID" InsertVisible="False" 
                    ReadOnly="True" SortExpression="ID" />
                <asp:BoundField DataField="Title" HeaderText="Title" SortExpression="Title" />
                <asp:BoundField DataField="Description" HeaderText="Description" 
                    SortExpression="Description" />
                <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
                <asp:BoundField DataField="Username" HeaderText="Username" 
                    SortExpression="Username" />
                <asp:BoundField DataField="DivisionShortcut" HeaderText="Division" 
                    SortExpression="DivisionShortcut" />
                <asp:TemplateField HeaderText="Status">
                    <ItemTemplate>
                        <asp:DropDownList ID="DropDownList" runat="server" DataSourceID="SqlDataSource2"
                                          Font-Bold="True" ForeColor="#006666" AppendDataBoundItems="false" 
                                          DataTextField="Status" DataValueField="ID" AutoPostBack="true" 
                                          OnDataBound="DropDownList_DataBound">
                        </asp:DropDownList>
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>
        <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
            ConnectionString="<%$ ConnectionStrings:testConnectionString %>" 
            SelectCommand="SELECT     dbo.SafetySuggestionsLog.ID, dbo.SafetySuggestionsLog.Title, dbo.SafetySuggestionsLog.Description, dbo.employee.Name, dbo.SafetySuggestionsLog.Username, 
                      dbo.Divisions.DivisionShortcut
FROM         dbo.employee INNER JOIN
                      dbo.SafetySuggestionsLog ON dbo.employee.Username = dbo.SafetySuggestionsLog.Username INNER JOIN
                      dbo.Divisions ON dbo.employee.DivisionCode = dbo.Divisions.SapCode"
                      FilterExpression="[DivisionShortcut] like '{0}%'">

                      <FilterParameters>
                        <asp:ControlParameter ControlID="ddlDivision" Name="DivisionShortcut" 
                                                 PropertyName="SelectedValue" Type="String" />
                    </FilterParameters>
        </asp:SqlDataSource>

        <%--For the DropDownList--%>
        <asp:SqlDataSource ID="SqlDataSource2" runat="server"
        ConnectionString="<%$ ConnectionStrings:testConnectionString %>" 
        SelectCommand="SELECT * FROM [SafetySuggestionsStatus]"></asp:SqlDataSource>

我的守则 - 背后：

protected void Page_Load(object sender, EventArgs e)
    {

    }

    int i = 1;
    protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            e.Row.Cells[0].Text = i.ToString();
            i++;
        }

    }

    protected void DropDownList_DataBound(object sender, EventArgs e)
    {

        if (!IsPostBack)
        {
            DropDownList.Items.Insert(0, new ListItem("--Select--", ""));
        }
    }

那我该如何解决这个问题呢？

Answer 1

基于您似乎得到的异常，您可能必须将DropDownList_DataBound事件中的发送者强制转换为DropDownList才能访问其Items集合：

protected void DropDownList_DataBound(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        ((DropDownList)sender).Items.Insert(0, new ListItem("--Select--", ""));
    }
}

Answer 2

这一切都在我的头脑中，所以代码可能不完美，但这就是你需要做的事情：

在RowDataBound中，从行中强制转换DropDownList的实例。

DropDownList drp = (DropDownList)e.Row.Cells[7].FindControl("DropDownList");

然后调用类似于下面的数据绑定函数

绑定您的datalist

protected void bindDrop(DropDownList drp)
{
  if (!IsPostBack)
  {
    drp.Items.Insert(0, new ListItem("--Select--", ""));
    drp.DataBind()
  }
 }

应该这样做

如何让这个DropDownList在GridView中运行？

2 个答案: