通过sql select语句显示ID和名称

Question

• 我有2个下拉列表，1个标签& 1个文本框。

• 选择“产品类别”@ 1st ddl，2nd ddl显示所有产品类别。

• 问题是，我怎么可能显示产品类别id @标签，并在加载/选择第二个ddl时显示文本框名称？

• 我有以下代码：

 

Public Sub FilterProductCategory() 
    Dim myConn As New SqlConnection 
    Dim myCmd As New SqlCommand 
    Dim dtrReader As SqlDataReader 


    myConn.ConnectionString = ConfigurationManager.ConnectionStrings("ConnectionString").ConnectionString 
    myCmd = myConn.CreateCommand 
    myCmd.CommandText = "SELECT product_category_id, product_category_name FROM ProductCategory ORDER BY product_category_name" 

    Try 
     myConn.Open() 
     dtrReader = myCmd.ExecuteReader() 

     If dtrReader.HasRows Then 
      DropDownList2.Items.Clear() 
      DropDownList2.DataSource = dtrReader 
      DropDownList2.DataValueField = "product_category_name" 
      DropDownList2.DataBind() 
     End If 
     dtrReader.Close() 
     myConn.Close() 
    Catch 
    End Try 
End Sub 

Answer 1

刚刚成立的：

DropDownList2.DataTextField = "product_category_name" 
DropDownList2.DataValueField = "product_category_id" 

所以当你尝试dropdownlist2.selectedvalue那么你将得到ID，当ü尝试dropdownlist2.selecteditem.text那么它会给你的产品类别名称..

希望它会解决你的问题

Answer 2

希望这有助于，听起来很简单。我假设您的标签和文本框的ID与下拉列表的格式相同。如果不是，请替换您自己的ID。此代码也完全运行在服务器端，这意味着您将刷新整个页面来完成这个相当简单的任务。如果这不是问题，那么通过一切手段使用这种方法，否则我会建议在客户端使用JavaScript来做到这一点。

Protected Sub DropDownList2_SelectedIndexChanged(Sender as Object, e as EventArgs) Handles DropDownList2.SelectedIndexChanged 
Label1.Text = DropDownList2.SelectedValue 
TextBox1.Text = DropDownList2.SelectedItem.Text 
End Sub 

Answer 3

首套DataTextField到您的下拉列表display text（类别名称）和DataValueField到您的下拉列表SelectedValue（categoryID）。

DropDownList2.DataTextField = "product_category_name"; 
DropDownList2.DataValueField = "product_category_id"; 

和DropDownList中的SelectIndexChanged Event使用SelectedValue属性来访问category ID AMD SelectedItem.Text访问Categoryname

Protected Sub DropDownList2_SelectedIndexChanged(Sender as Object, e as EventArgs) Handles DropDownList2.SelectedIndexChanged 
Label1.Text = DropDownList2.SelectedValue 
TextBox1.Text = DropDownList2.SelectedItem.Text 
End Sub 

检查DropDownList Class有关这些属性的信息等。

检查这个例子：

protected void Page_Load(object sender, EventArgs e) 
     { 
      if (!IsPostBack) 
      { 
       BindList(); 
      } 
     } 

     private void BindList() 
     { 
      SqlConnection con = new SqlConnection("server=.\\sqlexpress;initial catalog=test;integrated security=true;"); 
      SqlDataReader reader; 
      SqlCommand command = con.CreateCommand(); 
      command.CommandText = "Select * from UserTable order by UserName"; 
      try 
      { 
       con.Open(); 
       reader = command.ExecuteReader(); 
       if (reader.HasRows) 
       { 
        DropDownList1.DataSource = reader; 
        DropDownList1.DataValueField = "userid"; 
        DropDownList1.DataTextField = "UserName"; 
        DropDownList1.DataBind(); 
       } 

       reader.Close(); 
       con.Close(); 
      } 
      catch (Exception) 
      { 
       throw; 
      } 
     } 

     protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) 
     { 
      Label1.Text = DropDownList1.SelectedValue; 
      TextBox1.Text = DropDownList1.SelectedItem.Text; 
     } 

输出///