DataSourceView.cs :  » 2.6.4-mono-.net-core » System.Web » System » Web » UI » C# / CSharp Open Source

//
// System.Web.UI.DataSourceView
//
// Authors:
//  Ben Maurer (bmaurer@users.sourceforge.net)
//  Sanjay Gupta (gsanjay@novell.com)
//
// (C) 2003 Ben Maurer
// (C) 2004-2010 Novell, Inc. (http://www.novell.com)
//

//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System.Collections;
using System.Collections.Specialized;
using System.Text;
using System.ComponentModel;

namespace System.Web.UI{
  public abstract class DataSourceView
  {
    //IDataSource dataSourceOwner;
    string viewName = String.Empty;

    protected DataSourceView (IDataSource owner, string viewName)
    {
      if (owner == null)
        throw new ArgumentNullException ("owner");

      //this.dataSourceOwner = owner;
      this.viewName = viewName;
      owner.DataSourceChanged += new EventHandler (OnDataSourceChanged);
    }

    void OnDataSourceChanged (object sender, EventArgs e) {
      OnDataSourceViewChanged (EventArgs.Empty);
    }

    public virtual void Delete (IDictionary keys, IDictionary values,
            DataSourceViewOperationCallback callBack)
    {
      if (callBack == null)
        throw new ArgumentNullException ("callBack");

      int rowAffected;
      try {
        rowAffected = ExecuteDelete (keys, values);
      }
      catch (Exception e) {
        if (!callBack (0, e))
          throw;
        return;
      }
      callBack (rowAffected, null);
    }

    protected virtual int ExecuteDelete(IDictionary keys, IDictionary values)
    {
      throw new NotSupportedException ();
    }

    protected virtual int ExecuteInsert (IDictionary keys)
    {
      throw new NotSupportedException();
    }

    protected internal abstract IEnumerable ExecuteSelect (
          DataSourceSelectArguments arguments);

    protected virtual int ExecuteUpdate (IDictionary keys, IDictionary values, 
                IDictionary oldValues )
    {
      throw new NotSupportedException ();
    }

    public virtual void Insert (IDictionary values, 
          DataSourceViewOperationCallback callBack)
    {
      if (callBack == null)
        throw new ArgumentNullException("callBack");

      int rowAffected;
      try {
        rowAffected = ExecuteInsert (values);
      } catch (Exception e) {
        if (!callBack (0, e))
          throw;
        return;
      }

      callBack (rowAffected, null);
    }

    protected virtual void OnDataSourceViewChanged (EventArgs eventArgs)
    {
      if (eventsList != null) {
        EventHandler evtHandler = eventsList [EventDataSourceViewChanged] as EventHandler;
        if (evtHandler != null)
          evtHandler(this, eventArgs);
      }
    }
    
    protected internal virtual void RaiseUnsupportedCapabilityError (
            DataSourceCapabilities capability)
    {
      if ((capability & DataSourceCapabilities.Sort) != 0)
        if (!CanSort)
          throw new NotSupportedException ("Sort Capabilites");

      if ((capability & DataSourceCapabilities.Page) != 0)
        if (!CanPage)
          throw new NotSupportedException("Page Capabilites");

      if ((capability & DataSourceCapabilities.RetrieveTotalRowCount) != 0)
        if (!CanRetrieveTotalRowCount)
          throw new NotSupportedException("RetrieveTotalRowCount Capabilites");

      return;
    }

    public virtual void Select (DataSourceSelectArguments selectArgs,
            DataSourceViewSelectCallback callBack)
    {
      if (callBack == null)
        throw new ArgumentNullException("callBack");

      selectArgs.RaiseUnsupportedCapabilitiesError (this);
      
      IEnumerable selectList = ExecuteSelect (selectArgs);
      callBack (selectList);
    }

    public virtual void Update(IDictionary keys, IDictionary values,
      IDictionary oldValues, DataSourceViewOperationCallback callBack)
    {
      if (callBack == null)
        throw new ArgumentNullException ("callBack");

      int rowAffected;
      try {
        rowAffected = ExecuteUpdate (keys, values, oldValues);
      } catch (Exception e) {
        if (!callBack (0, e))
          throw;
        return;
      }

      callBack (rowAffected, null);
    } 
    
    public virtual bool CanDelete { get { return false; } }
    public virtual bool CanInsert { get { return false; } }
    public virtual bool CanPage { get { return false; } }
    public virtual bool CanRetrieveTotalRowCount { get { return false; } }
    public virtual bool CanSort { get { return false; } }
    public virtual bool CanUpdate { get { return false; } }

    EventHandlerList eventsList;
    protected EventHandlerList Events {
      get {
        if (eventsList == null)
          eventsList = new EventHandlerList();

        return eventsList;
      }
    }
    
    internal bool HasEvents ()
    {
      return eventsList != null;
    }

    public string Name { 
      get { return viewName; } 
    }

    static readonly object EventDataSourceViewChanged = new object ();
        
    public event EventHandler DataSourceViewChanged
    {
      add { Events.AddHandler (EventDataSourceViewChanged, value); }
      remove { Events.RemoveHandler (EventDataSourceViewChanged, value); }
    }
    
  }
  
}