从sql数据源将dropdownlist与optGroup绑定

从sql数据源将dropdownlist与optGroup绑定

您可以编写一个自定义服务器控件，并使用包含以 | 分隔的文本和区域的数据源 。 然后在使用时将其拆分。

[ToolboxData("<{0}:CustomDropDownList runat=server></{0}:CustomDropDownList>")]public class CustomDropDownList : DropDownList{    protected override void RenderContents(HtmlTextWriter writer)    {        if (this.Items.Count > 0)        { bool selected = false; bool optGroupStarted = false; string lastOptionGroup = string.Empty; for (int i = 0; i < this.Items.Count; i++) {     ListItem item = this.Items[i];     if (item.Enabled)     {         if (lastOptionGroup != item.Text.Split("|")[1])         {  if (optGroupStarted)  {      writer.WriteEndTag("optgroup");  }  lastOptionGroup = item.Text.Split("|")[1];  writer.WriteBeginTag("optgroup");  writer.WriteAttribute("label", lastOptionGroup);  writer.Write('>');  writer.WriteLine();  optGroupStarted = true;         }         writer.WriteBeginTag("option");         if (item.Selected)         {  if (selected)  {      this.VerifyMultiSelect();  }  selected = true;  writer.WriteAttribute("selected", "selected");         }         writer.WriteAttribute("value", item.Value, true);         if (item.Attributes.Count > 0)         {  item.Attributes.Render(writer);         }         if (this.Page != null)         {  this.Page.Clientscript.RegisterForEventValidation(this.UniqueID, item.Value);         }         writer.Write('>');         HttpUtility.HtmlEnpre(item.Text.Split("|")[0], writer);         writer.WriteEndTag("option");         writer.WriteLine();     } } if (optGroupStarted) {     writer.WriteEndTag("optgroup"); }        }    }}