class/System.Web/System.Web.UI/DataSourceSelectArguments.cs

   1 //
   2 // System.Web.UI.DataSourceSelectArguments.cs
   3 //
   4 // Author:
   5 //   Sanjay Gupta <gsanjay@novell.com>
   6 //
   7 // (C) 2004-2010 Novell, Inc (http://www.novell.com)
   8 //
   9
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 using System;
  32
  33 namespace System.Web.UI
  34 {
  35         public sealed class DataSourceSelectArguments
  36         {
  37                 string sortExpression;
  38                 int startingRowIndex;
  39                 int maxRows;
  40                 bool getTotalRowCount;
  41                 int totalRowCount = -1;
  42                 DataSourceCapabilities dsc = DataSourceCapabilities.None;
  43
  44                 // MSDN: Gets a DataSourceSelectArguments object with the sort expression set to Empty.
  45                 public static DataSourceSelectArguments Empty {
  46                         get {
  47                                 return new DataSourceSelectArguments ();
  48                         }
  49                 }
  50
  51                 public DataSourceSelectArguments ()
  52                 {
  53                 }
  54
  55                 public DataSourceSelectArguments (string sortExpression)
  56                 {
  57                         this.sortExpression = sortExpression;
  58                 }
  59
  60                 public DataSourceSelectArguments (int startingRowIndex, int maxRows)
  61                 {
  62                         this.startingRowIndex = startingRowIndex;
  63                         this.maxRows = maxRows;
  64                 }
  65
  66                 public DataSourceSelectArguments (string sortExpression, int startingRowIndex, int maxRows)
  67                 {
  68                         this.sortExpression = sortExpression;
  69                         this.startingRowIndex = startingRowIndex;
  70                         this.maxRows = maxRows;
  71                 }
  72
  73                 public void AddSupportedCapabilities (DataSourceCapabilities srcCapabilities)
  74                 {
  75                         this.dsc = this.dsc | srcCapabilities;
  76                 }
  77
  78                 // MSDN: The DataSourceSelectArguments class overrides the Object.Equals method to test
  79                 // equality using the various properties of the objects. If the MaximumRows,
  80                 // RetrieveTotalRowCount, SortExpression, StartRowIndex, and TotalRowCount properties
  81                 // are all equal in value, the Equals(Object) method returns true.
  82                 public override bool Equals (object obj)
  83                 {
  84                         DataSourceSelectArguments args = obj as DataSourceSelectArguments;
  85                         if (args == null)
  86                                 return false;
  87
  88                         return (this.SortExpression == args.SortExpression &&
  89                                 this.StartRowIndex == args.StartRowIndex &&
  90                                 this.MaximumRows == args.MaximumRows &&
  91                                 this.RetrieveTotalRowCount == args.RetrieveTotalRowCount &&
  92                                 this.TotalRowCount == args.TotalRowCount);
  93                 }
  94
  95                 public override int GetHashCode ()
  96                 {
  97                         int hash = SortExpression != null ? SortExpression.GetHashCode() : 0;
  98                         return hash ^ StartRowIndex ^ MaximumRows ^ RetrieveTotalRowCount.GetHashCode() ^ TotalRowCount;
  99                 }
 100
 101                 // The RaiseUnsupportedCapabilitiesError method is used by data-bound controls
 102                 // to compare additional requested capabilities represented by the properties
 103                 // of the DataSourceSelectArguments class, such as the ability to sort or page
 104                 // through a result set, with the capabilities supported by the data source view.
 105                 // The view calls its own RaiseUnsupportedCapabilityError method for each possible
 106                 // capability defined in the DataSourceCapabilities enumeration.
 107                 public void RaiseUnsupportedCapabilitiesError (DataSourceView view)
 108                 {
 109                         DataSourceCapabilities requestedCaps = RequestedCapabilities;
 110                         DataSourceCapabilities notSupportedCaps = (requestedCaps ^ dsc) & requestedCaps;
 111                         if (notSupportedCaps == DataSourceCapabilities.None)
 112                                 return;
 113
 114                         if ((notSupportedCaps & DataSourceCapabilities.RetrieveTotalRowCount) > 0)
 115                                 notSupportedCaps = DataSourceCapabilities.RetrieveTotalRowCount;
 116                         else if ((notSupportedCaps & DataSourceCapabilities.Page) > 0)
 117                                 notSupportedCaps = DataSourceCapabilities.Page;
 118
 119                         view.RaiseUnsupportedCapabilityError (notSupportedCaps);
 120                 }
 121
 122                 DataSourceCapabilities RequestedCapabilities {
 123                         get {
 124                                 DataSourceCapabilities caps = DataSourceCapabilities.None;
 125                                 if (!String.IsNullOrEmpty (SortExpression))
 126                                         caps |= DataSourceCapabilities.Sort;
 127                                 if (RetrieveTotalRowCount)
 128                                         caps |= DataSourceCapabilities.RetrieveTotalRowCount;
 129                                 if (StartRowIndex > 0 || MaximumRows > 0)
 130                                         caps |= DataSourceCapabilities.Page;
 131                                 return caps;
 132                         }
 133                 }
 134
 135                 public int MaximumRows {
 136                         get { return this.maxRows; }
 137                         set { this.maxRows = value; }
 138                 }
 139
 140                 public bool RetrieveTotalRowCount  {
 141                         get { return this.getTotalRowCount; }
 142                         set { this.getTotalRowCount = value; }
 143                 }
 144
 145                 public string SortExpression {
 146                         get {
 147                                 if (sortExpression == null)
 148                                         return String.Empty;
 149                                 return this.sortExpression;
 150                         }
 151                         set { this.sortExpression = value; }
 152                 }
 153
 154                 public int StartRowIndex {
 155                         get { return this.startingRowIndex; }
 156                         set { this.startingRowIndex = value; }
 157                 }
 158
 159                 public int TotalRowCount {
 160                         get { return this.totalRowCount; }
 161                         set { this.totalRowCount = value; }
 162                 }
 163         }
 164 }