如何在Listbox上设置多个SelectedItem？

Question

示例代码是这样的：

<asp:Listbox ID="ddlCat" runat="server" SelectionMode="Multiple" /> 

ddlCat.Items.Insert(0, new ListItem("Item1", "1")); 

ddlCat.Items.Insert(1, new ListItem("Item2", "2")); 

ddlCat.Items.Insert(2, new ListItem("Item3", "3")); 

ddlCat.Items.Insert(3, new ListItem("Item4", "4")); 

我要上项目1和项目3设置2默认将selectedItem，如何做到这一点？

使用这些代码，只有最新的必选

ddlCat.SelectedValue = "1"; 

ddlCat.SelectedValue = "3"; 

非常感谢！

Answer 1

我找到了解决办法

ddlCat.Items.FindByValue("1").Selected = true; 
ddlCat.Items.FindByValue("3").Selected = true; 

Answer 2

{if (e.Row.RowType == DataControlRowType.DataRow && gridView.EditIndex == e.Row.RowIndex) 
       { 
        ListBox ddl_Makeid = (ListBox)e.Row.FindControl("lst_hopid"); 
        DataSet ds = new DataSet(); 
        con.Open(); 
        string cmdstr = "SELECT HeadsOfPricingId,HeadsOfPricing FROM tblHeadsOfPricing"; 
        SqlCommand cmd = new SqlCommand(cmdstr, con); 
        SqlDataAdapter adp = new SqlDataAdapter(cmd); 
        adp.Fill(ds); 
        ddl_Makeid.DataSource = ds.Tables[0]; 
        ddl_Makeid.DataTextField = "HeadsOfPricing"; 
        ddl_Makeid.DataValueField = "HeadsOfPricingId"; 
        DataRowView drv = e.Row.DataItem as DataRowView; 
        ddl_Makeid.DataBind(); 
        con.Close(); 

        Label lbl_texbox = (Label)e.Row.FindControl("lbl_hopId_edit"); 
        string stsplit = lbl_texbox.Text; 
        char[] splichar = { ',' }; 
        string[] strarray = stsplit.Split(splichar); 

        //ListBox listbox = (ListBox)e.Row.FindControl("lst_hopid"); 
        ListBox listboxtest = new ListBox(); 
        for (int x = 0; x < strarray.Length; x++) 
        { 
         if (strarray[x] != null && strarray[x] !="") 
         { 
          //ddl_Makeid.SelectedValue += strarray[x]; 
          ddl_Makeid.Items.FindByValue(strarray[x]).Selected = true; 
          //listboxtest = (ListBox)e.Row.Cells[x].FindControl("Lst_New_hopid"); 
         } 
        } 


       }}