publisherlistconverter.cs

ASP.NET服务器控件高级编程电子书

using System;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Data.SqlClient;
using System.Data;
using WroxDesign;

namespace WroxDesign.Design
{
	public class PublisherListConverter : TypeConverter
	{
		public PublisherListConverter()
		{
		}

		private static StandardValuesCollection _publisher;
		//Change to point to your pubs database
		private static string _connection = @"data source=DEVMOVIL\NETSDK;initial catalog=pubs;password=;user id=sa;";
	
		private StandardValuesCollection ListInstance()
		{
			if (_publisher == null)
			{
				DataSet ds = new DataSet();
				SqlDataAdapter ad = new SqlDataAdapter(
					"SELECT pub_name FROM publishers", _connection);
				ad.Fill(ds);

				//Build an array and pass it to the StandardValuesCollection constructor
				string[] pubs = new string[ds.Tables[0].Rows.Count];
				for (int i = 0; i < pubs.Length; i++)
					pubs[i] = ds.Tables[0].Rows[i][0].ToString();
				_publisher = new StandardValuesCollection(pubs);
			}
			return _publisher;
		}
 
		public override bool GetStandardValuesSupported(
			ITypeDescriptorContext context) 
		{
			return true;
		}

		public override bool GetStandardValuesExclusive(
			ITypeDescriptorContext context) 
		{
			// Return false to allow not listed values.      
			return true;
		}

		public override StandardValuesCollection GetStandardValues(
			ITypeDescriptorContext context) 
		{	
			return ListInstance();
		}
	}
}