扩展项目工具提示，Asp.net，C＃的下拉列表

Question

i need to extend the DropDownList For adding toolTip For DropDown Item On mouseOver.

If(Dropdown size is samller than Dropdownlist item then it will be useful for seeing the item as tool tip)

For that i came to know, We need to create ServerControl project in VS2008 but i dont know how to add a property like ItemToolTip

which need to be worked as (DataTextField, DataValueField in drop down list) in that class .

tell me any link for ServerControl project sample which resembles my requirement.

I tried using below code but dropdown property itself not working..

namespace DropDownItemToolTip

{

[DefaultProperty("Text")]
[ToolboxData("<{0}:ServerControl1 runat=server></{0}:ServerControl1>")]

public class ServerControl1 : System.Web.UI.WebControls.DropDownList 
{

    [Bindable(true)]
    [Category("Appearance")]
    [DefaultValue("")]
    [Localizable(true)]
    public  string Text1
    {
        get
        {
            String s = (String)ViewState["Text"];
            return ((s == null) ? "[" + this.ID + "]" : s);
        }

        set
        {
            ViewState["Text"] = value;
        }
    }

    protected override void RenderContents(HtmlTextWriter output)
    {
        output.Write(Text1);
    }

}

}

Send me any sample project link, which done like this..

Answer 1

Why you want to extend the Dropdownlist? Try adding a Title tag will work right?

Try this code

<select>
    <option title="this is a long text">Long text</option>
</select>

It will show a this is a long text tooltip on mouseover.

Answer 2

Try this:

using System.Collections;
using System.ComponentModel;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace Foo
{
    [ToolboxData("<{0}:DDL runat=\"server\" />")]
    public class DDL : DropDownList
    {

        [Category("Data"), DefaultValue("")]
        public string DataToolTipField
        {
            get { return (string)(ViewState["DataToolTipField"] ?? string.Empty); }
            set { ViewState["DataToolTipField"] = value; }
        }

        protected override void PerformDataBinding(IEnumerable dataSource)
        {
            base.PerformDataBinding(dataSource);

            string dataToolTipField = this.DataToolTipField;

            if (!string.IsNullOrEmpty(dataToolTipField))
            {
                IEnumerator enumerator = dataSource.GetEnumerator();
                for (int i = 0; enumerator.MoveNext(); i++)
                {
                    this.Items[i].Attributes.Add("title", (string)DataBinder.GetPropertyValue(enumerator.Current, dataToolTipField));
                }
            }
        }

    }
}