A DataTable Serializer for ASP.NET AJAX（转载）

此文转载自http://www.dennydotnet.com/post/2007/09/A-DataTable-Serializer-for-ASPNET-AJAX.aspx，未作翻译。

A DataTable Serializer for ASP.NET AJAX, implements JavaScriptConverter. Note that I did not implement a Deserialize method since I am using this for read only data.

[code:c#]

/**//// <summary>
/// DataTable to JSON converter
/// </summary>
public class JavaScriptDataTableConverter : JavaScriptConverter {
 public override object Deserialize( IDictionary<string, object> dictionary, Type type, JavaScriptSerializer serializer ) {
  throw new NotImplementedException( "Deserialize is not implemented." );
 } 

 public override IDictionary<string, object> Serialize( object obj, JavaScriptSerializer serializer ) {
  DataTable dt = obj as DataTable;
  Dictionary<string, object> result = new Dictionary<string, object>(); 

  if( dt != null && dt.Rows.Count > 0 ) {
   // List for row values
   List<object> rowValues = new List<object>(); 

   foreach( DataRow dr in dt.Rows ) {
    // Dictionary for col name / col value
    Dictionary<string, object> colValues = new Dictionary<string, object>(); 

    foreach( DataColumn dc in dt.Columns ) {
     colValues.Add( dc.ColumnName, // col name
      ( string.Empty == dr[dc].ToString() ) ? null : dr[dc] ); // col value
    } 

    // Add values to row
    rowValues.Add( colValues );
   } 

   // Add rows to serialized object
   result["rows"] = rowValues;
  } 

  return result;
 } 

 public override IEnumerable<Type> SupportedTypes {
  //Define the DataTable as a supported type.
  get {
   return new System.Collections.ObjectModel.ReadOnlyCollection<Type>(
    new List<Type>(
     new Type[] { typeof( DataTable ) }
    )
   );
  }
 }
}

[/code]

 

And how do you implement this? In a web service...

[code:c#]

using System.Web.Script.Serialization; 

//  

[WebMethod()]
[ScriptMethod( ResponseFormat = ResponseFormat.Json )]
public string TestJS( int Id ) {
 JavaScriptSerializer toJSON = new JavaScriptSerializer();
 toJSON.RegisterConverters( new JavaScriptConverter[] { new JavaScriptDataTableConverter() } ); 

 DataTable dt = new Query( Log.Schema )
   .WHERE( Log.Columns.ID, Id )
   .ExecuteDataSet().Tables[0]; 

 return toJSON.Serialize( dt );
}

[/code]

 

That's all there is to it! Just deserialize to an object on the client-side and you're good to go!

Side Note: There is a DataTable serializer from Microsoft in the ASP.NET Futures package.