Datalist ASP.NET 中的 Gridview

Question

我正在尝试在 asp 数据列表中放置一个 asp gridview。对于数据列表中的每个项目，我希望返回另一个数据库表中的某些值。

我写了以下代码，但是gridview没有返回数据（我可以确认数据库中有记录并且存储过程是正确的）。 asp 数据列表工作正常。

我做错了什么没有填充gridview？

<asp:DataList runat="server" id="listResponses" DataKeyField="QuestionID" CssClass="confirm" OnItemDataBound="listResponses_ItemDataBound">
    <ItemTemplate>
    <h3 class="confirm new">Question <asp:Label ID="lblaOrder" runat="server" Text='<%# Container.ItemIndex  + 1 %>'></asp:Label></h3>
    <div class="confirm_question">
        <asp:Label ID="lblOrder" runat="server" Text='<%# Container.ItemIndex  + 1 %>'></asp:Label>
        <p class="confirm"><%# DataBinder.Eval(Container.DataItem, "QuestionText") %></p>
    </div> <!-- end confirm_question -->
    <asp:GridView runat="server" ID="gridResponses" DataKeyNames="QuestionID"">
        <Columns>
            <asp:BoundField DataField="AnswerTitle" HeaderText="ID" HeaderStyle-Width="80px" ItemStyle-CssClass="bo"></asp:BoundField>
            <asp:BoundField DataField="Responses" HeaderText="Response Count" HeaderStyle-Width="150px" />
         </Columns>
      </asp:GridView>   
  </ItemTemplate> 
</asp:DataList>

这是背后的代码。

public partial class questionnaire_responses : System.Web.UI.Page
{
    OsqarSQL GetData;
    DataTable DT;
    private string _productConnectionString;
    private SqlConnection _productConn;      

    protected void Page_Load(object sender, EventArgs e) 
    { 
        string questionnaireId = Session["qID"].ToString();
        int qid = Convert.ToInt32(questionnaireId);
        GetData = new OsqarSQL();
        string name = GetData.GetQuestionnaireName(qid);
        lblQuestionnaireName.Text = name;
        if (!IsPostBack) 
        { 
            DT = GetData.GetQuestionNameDataList(qid);
            listResponses.DataSource = DT;
            listResponses.DataBind();
        } 
    }

    private void BindGrid(GridView GridView, int questionId) 
    {
        DataTable dt = new DataTable(); 
        GetData.GetAnswerTitle(questionId);
        GridView.DataSource = dt; 
        GridView.DataBind();
    }

    protected void listResponses_ItemDataBound(object sender, DataListItemEventArgs e) 
    { 
        GridView gridResponses=(GridView)e.Item.FindControl("gridResponses"); 
        BindGrid(gridResponses, (int)listResponses.DataKeys[e.Item.ItemIndex]); 
    }

}

//Method from the data access class
public DataTable GetAnswerTitle(int QuestionId)
{
    string returnValue = string.Empty;
    SqlCommand myCommand = new SqlCommand("GetAnswer", _productConn);
    myCommand.CommandType = CommandType.StoredProcedure;
    ,yCommand.Parameters.Add(new SqlParameter("@QUESTION_ID", SqlDbType.Int));
    myCommand.Parameters[0].Value = QuestionId;
    return createDataTable(getData(myCommand));
}

Answer 1

您已为您的 GridView 创建了一个空的 DataTable 为 DataSource。

替换

DataTable dt = new DataTable(); 
GetData.GetAnswerTitle(questionId);
GridView.DataSource = dt; 

有了这个

DataTable dt = GetData.GetAnswerTitle(questionId);
GridView.DataSource = dt;