DataList 不显示数据

Question

所以我有一个数据源和一个数据列表：

 <asp:SqlDataSource ID="SearchDataSource" runat="server" 
        ConnectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|WheelsDB.mdb;Persist Security Info=True" 
        ProviderName="System.Data.OleDb">
        </asp:SqlDataSource>
  <asp:DataList ID="DataList1" runat="server" DataSourceID="SearchDataSource"></asp:DataList>

当用户点击一个按钮时，它会执行这段代码，根据用户的选择修改查询：

query = "SELECT * FROM Cars WHERE "

if(make != 1)
{
   query = query + "make_id = @make";
   SearchDataSource.SelectParameters.Add("make", make.ToString());
}

SearchDataSource.SelectCommand = query;
btn_search.Text = DataList1.Items.Count.ToString();

然而，当数据列表应该显示一些行时，btn_search.Text 显示 0 而数据列表中没有显示行，有人知道我做错了什么吗？

Answer 1

您应该在查询中添加 where 子句。

C#

query = "SELECT * FROM Cars"

if(make != 1)
{
   query = query + " where make_id = @make"; // add here
   SearchDataSource.SelectParameters.Add("make", make.ToString());
}

SearchDataSource.SelectCommand = query;
btn_search.Text = DataList1.Items.Count.ToString();

ASPX

<asp:DataList ID="DataList1" runat="server" DataSourceID="SearchDataSource">
    <ItemTemplate>
        <asp:Label ID="lblmake_id" runat="server" Text='<%# Eval("make_id")%>' />
    </ItemTemplate>
</asp:DataList>

DataList 不显示数据

DataList not displaying data

c#

asp.net

datalist