mcs/class/referencesource/System.Data/System/Data/DataColumnPropertyDescriptor.cs

   1 //------------------------------------------------------------------------------
   2 // <copyright file="DataColumnPropertyDescriptor.cs" company="Microsoft">
   3 //     Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 // <owner current="true" primary="true">Microsoft</owner>
   6 // <owner current="true" primary="false">Microsoft</owner>
   7 // <owner current="false" primary="false">Microsoft</owner>
   8 //------------------------------------------------------------------------------
   9
  10 namespace System.Data {
  11     using System.Diagnostics;
  12     using System.ComponentModel;
  13     using System.Data.Common;
  14
  15     internal sealed class DataColumnPropertyDescriptor : PropertyDescriptor {
  16
  17         DataColumn column;
  18
  19         internal DataColumnPropertyDescriptor(DataColumn dataColumn) : base(dataColumn.ColumnName, null) {
  20             this.column = dataColumn;
  21         }
  22
  23         public override AttributeCollection Attributes {
  24             get {
  25                 if (typeof(System.Collections.IList).IsAssignableFrom(this.PropertyType)) {
  26                     Attribute[] attrs = new Attribute[base.Attributes.Count + 1];
  27                     base.Attributes.CopyTo(attrs, 0);
  28                     // we don't want to show the columns which are of type IList in the designer
  29                     attrs[attrs.Length - 1] = new ListBindableAttribute(false);
  30                     return new AttributeCollection(attrs);
  31                 } else {
  32                     return base.Attributes;
  33                 }
  34             }
  35         }
  36
  37         internal DataColumn Column {
  38             get {
  39                 return column;
  40             }
  41         }
  42
  43         public override Type ComponentType {
  44             get {
  45                 return typeof(DataRowView);
  46             }
  47         }
  48
  49         public override bool IsReadOnly {
  50             get {
  51                 return column.ReadOnly;
  52             }
  53         }
  54
  55         public override Type PropertyType {
  56             get {
  57                 return column.DataType;
  58             }
  59         }
  60
  61         public override bool Equals(object other) {
  62             if (other is DataColumnPropertyDescriptor) {
  63                 DataColumnPropertyDescriptor descriptor = (DataColumnPropertyDescriptor) other;
  64                 return(descriptor.Column == Column);
  65             }
  66             return false;
  67         }
  68
  69         public override Int32 GetHashCode() {
  70             return Column.GetHashCode();
  71         }
  72
  73         public override bool CanResetValue(object component) {
  74             DataRowView dataRowView = (DataRowView) component;
  75             if (!column.IsSqlType)
  76                 return (dataRowView.GetColumnValue(column) != DBNull.Value);
  77             return (!DataStorage.IsObjectNull(dataRowView.GetColumnValue(column)));
  78         }
  79
  80         public override object GetValue(object component) {
  81             DataRowView dataRowView = (DataRowView) component;
  82             return dataRowView.GetColumnValue(column);
  83         }
  84
  85         public override void ResetValue(object component) {
  86             DataRowView dataRowView = (DataRowView) component;
  87             dataRowView.SetColumnValue(column, DBNull.Value);// no need to ccheck for the col type and set Sql...Null!
  88         }
  89
  90         public override void SetValue(object component, object value) {
  91             DataRowView dataRowView = (DataRowView) component;
  92             dataRowView.SetColumnValue(column, value);
  93             OnValueChanged(component, EventArgs.Empty);
  94         }
  95
  96         public override bool ShouldSerializeValue(object component) {
  97             return false;
  98         }
  99
 100                 public override bool IsBrowsable {
 101                         get {
 102                                 return (column.ColumnMapping == System.Data.MappingType.Hidden ? false : base.IsBrowsable);
 103                         }
 104                 }
 105     }
 106 }