将同一个数据源分配给多个DropDownLists？

我想给一个表单中的多个DropDownLists分配相同的数据源，当页面加载时，只有第一个下拉列表填充了数据源的内容，其他的是空的，缺少的是什么？感谢您的回答。这里是代码;将同一个数据源分配给多个DropDownLists？

<form id="form1" runat="server">  
    <asp:ScriptManager ID="scriptManager1" runat="server"></asp:ScriptManager> 
<asp:UpdatePanel ID="panel1" runat="server" UpdateMode="Conditional"> 
    <ContentTemplate> 
    <div id="div1" align="center"> 
     <table> 
     <tr> 
     <td><b>Brand-Model</b></td> 
     <td><asp:TextBox ID="brandText" runat="server" BorderStyle="Inset"></asp:TextBox></td> 
     <td><asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="brandText" Display="Dynamic" ErrorMessage="*"></asp:RequiredFieldValidator></td> 
     </tr> 
     <tr> 
     <td><b>Black</b></td> 
     <td><asp:DropDownList ID="blackList" runat="server"></asp:DropDownList></td> 
     <td><asp:HyperLink ID="HyperLink1" runat="server" Text="Add Cartridge" NavigateUrl="~/Admin/addCartridge.aspx"></asp:HyperLink></td> 
     </tr> 
     <tr> 
     <td><b>Color1</b></td> 
     <td><asp:DropDownList ID="colorList1" runat="server"></asp:DropDownList></td> 
     </tr> 
     <tr> 
     <td><b>Color2</b></td> 
     <td><asp:DropDownList ID="colorList2" runat="server"></asp:DropDownList></td> 
     </tr> 
     <tr> 
     <td><b>Color3</b></td> 
     <td><asp:DropDownList ID="colorList3" runat="server"></asp:DropDownList></td> 
     </tr> 
     <tr> 
     <td><b>Other1</b></td> 
     <td><asp:DropDownList ID="otherColor1" runat="server"></asp:DropDownList></td> 
     </tr> 
     <tr> 
     <td><b>Other2</b></td> 
     <td><asp:DropDownList ID="otherColor2" runat="server"></asp:DropDownList></td> 
     </tr> 
     <tr> 
     <td><b>Other3</b></td> 
     <td><asp:DropDownList ID="otherColor3" runat="server"></asp:DropDownList></td> 
     </tr> 
     <tr> 
     <td></td> 
     <td><asp:Button ID="submit" runat="server" Text="Submit" OnClick="submit_OnClick" /></td>  
     </tr>    
     <tr> 
     <td></td> 
     <td><asp:Label ID="submitInfo" runat="server"></asp:Label></td>  
     </tr> 
     </table> 
    </div> 
    </ContentTemplate> 
    <Triggers> 
     <asp:AsyncPostBackTrigger ControlID="submit" EventName="Click" /> 
    </Triggers> 
    </asp:UpdatePanel> 
</form>

protected void FillTheDropDownLists() 
    { 
     SqlApplication con = new SqlApplication(); 
     try 
     { 
      SqlCommand cmd = new SqlCommand("SELECT name FROM BT.dbo.Cartridge ORDER BY name", con.GetConnection()); 
      con.OpenSqlConnection(); 

      SqlDataReader reader = cmd.ExecuteReader(); 

      blackList.DataValueField = "name"; 
      blackList.DataSource = reader; 
      blackList.DataBind(); 

      colorList1.DataValueField = "name"; 
      colorList1.DataSource = reader; 
      colorList1.DataBind(); 

      colorList2.DataValueField = "name"; 
      colorList2.DataSource = reader; 
      colorList2.DataBind(); 

      colorList3.DataValueField = "name"; 
      colorList3.DataSource = reader; 
      colorList3.DataBind(); 

      otherColor1.DataValueField = "name"; 
      otherColor1.DataSource = reader; 
      otherColor1.DataBind(); 

      otherColor2.DataValueField = "name"; 
      otherColor2.DataSource = reader; 
      otherColor2.DataBind(); 

      otherColor3.DataValueField = "name"; 
      otherColor3.DataSource = reader; 
      otherColor3.DataBind(); 

      reader.Close(); 
     } 
     catch (Exception err) 
     { 
      System.Diagnostics.Debug.WriteLine("Exception: " + err.Message); 
     } 
     finally 
     { 
      con.CloseSqlConnection(); 
     } 
    }

来源

2010-06-25 anarhikos

其becasue您正在使用的DataReader，而不是使用这个数据表会为你工作。读者只读和转发这只是为什么只有第一dropdonw充满数据和其他人是空的。

改变的代码：

protected void FillTheDropDownLists() 
    { 
     SqlApplication con = new SqlApplication(); 
     try 
     { 
      SqlCommand cmd = new SqlCommand("SELECT name FROM BT.dbo.Cartridge ORDER BY name", con.GetConnection()); 
      con.OpenSqlConnection(); 

      SqlDataReader reader = cmd.ExecuteReader(); 
      DataTable dt = new DataTable(); 
      dt.Load(reader); 

      blackList.DataValueField = "name"; 
      blackList.DataSource = dt ; 
      blackList.DataBind(); 

      colorList1.DataValueField = "name"; 
      colorList1.DataSource = dt ; 
      colorList1.DataBind(); 

      colorList2.DataValueField = "name"; 
      colorList2.DataSource = reader; 
      colorList2.DataBind(); 

      colorList3.DataValueField = "name"; 
      colorList3.DataSource = dt ; 
      colorList3.DataBind(); 

      otherColor1.DataValueField = "name"; 
      otherColor1.DataSource = dt ; 
      otherColor1.DataBind(); 

      otherColor2.DataValueField = "name"; 
      otherColor2.DataSource = dt ; 
      otherColor2.DataBind(); 

      otherColor3.DataValueField = "name"; 
      otherColor3.DataSource = dt ; 
      otherColor3.DataBind(); 

      reader.Close(); 
     } 
     catch (Exception err) 
     { 
      System.Diagnostics.Debug.WriteLine("Exception: " + err.Message); 
     } 
     finally 
     { 
      con.CloseSqlConnection(); 
     } 
    }

来源

2010-06-25 10:43:22

非常感谢，它已经奏效，但是这次又有另外一个问题，发布表单后，每个选定的值都是内容的第一个值。它不会选择真正选定的值。哪里可以解决问题？ – anarhikos 2010-06-25 11:09:35

检查视图状态属性，因为我认为它没有持有状态后发回 – 2010-06-25 11:16:02

解决，非常感谢 – anarhikos 2010-06-25 12:15:36

按照documentation数据读取器是仅正向。使用数据表或读入列表并将您的组合连接到它。

来源

2010-06-25 10:45:29 Patko

输入代码在这里

 for (int i = 1; i <= 260; i++) 
     { 
      ContentPlaceHolder maincontent = Page.Master.FindControl("MainContent") as ContentPlaceHolder; 
      DropDownList a = (DropDownList)maincontent.FindControl("ddl" + i); 



      a.DataSource = ds; 
      a.DataTextField = "Options"; 
      a.DataValueField = "id"; 
      a.DataBind(); 
      a.Items.Insert(0, new ListItem("Select", "0", true)); 
     }

真正简单的代码。

来源

2017-08-23 06:44:26

将同一个数据源分配给多个DropDownLists？

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