Silverlight实战示例补充（数据集模拟挂接事件）

这里是部分代码，其它代码见Silverlight实战示例，直接上代码：

1）DynamicDataField.cs
[Serializable]
public partial class DynamicDataField
{
public string FieldName { get; set; }
public string StrValue { get; set; }
public DateTime DTValue { get; set; }
public Byte[] ByteArrayValue { get; set; }
public string DataType { get; set; }
//增加一个脏标志
public bool IsDirty { get; set; }
}

2)DynamicDataField.Shared.cs
public partial class DynamicDataField
{
public object OldValue { get; set; }
/// <summary>
/// 用object在绑定时没问题，但不能双向赋值，所以更新不采用这种方式.
/// </summary>
public object Value
{
get
{
if (this.DataType == "datatime")
{
return this.DTValue;
}
if (this.DataType == "byte[]")
{
return this.ByteArrayValue;
}
return this.StrValue;
}
set
{
object theOldValue = null;
if (this.DataType == "datatime")
{
theOldValue = DTValue;
DTValue = (DateTime) value;
}
else if (this.DataType == "byte[]")
{
theOldValue = this.ByteArrayValue;
this.ByteArrayValue = (byte[])value;
}
else
{
this.StrValue = value.ToString();
theOldValue = this.StrValue;
}
OldValue = theOldValue;
IsDirty = true;
if (DataFieldChanged != null)
{
DataFieldChanged(this, OldValue, value);
}
if (DataMemberChanged != null)
{
DataMemberChanged("Value");
}
}
}
public MyRaiseDataMemberChanged DataMemberChanged {get;set;}
//数据字段发生改变时的事件触发，用事件也可以。
public DataFieldChanged DataFieldChanged { get; set; }
}
//定义委托用于事件
public delegate void MyRaiseDataMemberChanged(string propertyName);
//数据改变时的委托定义
public delegate void DataFieldChanged(DynamicDataField Field, object OldValue, object NewValue);
public enum RowState
{
NoChanging,
Changed,
Inserted,
Deleted
}

3) DynamicDataRow.Shared.cs
public partial class DynamicDataRow
{
public DynamicDataField this[string FieldName]
{
get
{
DynamicDataField theField = null;
foreach (var fld in DataFields)
{
if (fld.FieldName == FieldName)
{
theField = fld;
break;
}
}
return theField;
}
}
public DynamicDataField this[int Index]
{
get
{
return DataFields[Index];
}
}
public void AcceptChanged()
{
foreach (var item in this.DataFields)
{
item.IsDirty = false;
item.OldValue = item.Value;
}
}
//判断行中的字段是否已经改变.
private bool RowHasChanged()
{
foreach (var item in this.DataFields)
{
if (item.IsDirty == true)
{
return true;
}
}
return false;
}
//本来可以直接调用Table的相关事件，但由于ComplexObject不能共享实例，以及维持类似DataTable和DataField,DataRow的关系
//不能穿越到客户端，所以这里采用比较笨的办法。主要提供给事件挂接.
internal void SetFieldEvent(DataFieldChanged FldEvent)
{
foreach (var item in this.DataFields)
{
item.DataFieldChanged = FldEvent;
}
this.DataFieldChanged = FldEvent;
}
public DataFieldChanged DataFieldChanged;
private RowState _RowState;
public RowState RowState {
get
{
if (_RowState == RowState.NoChanging)
{
if (RowHasChanged() == true)
{
_RowState = RowState.Changed;
}
}
return _RowState;
}
set
{
_RowState = value;
}
}
}

4)DynamicDataTable.Shared.cs
public partial class DynamicDataTable
{
public DynamicDataColumn this[string FieldName]
{
get
{
DynamicDataColumn theCol = null;
foreach (var col in Columns)
{
if (col.FieldName == FieldName)
{
theCol = col;
break;
}
}
return theCol;
}
}
public DynamicDataColumn this[int Index]
{
get
{
return Columns[Index];
}
}
public void AcceptChanged()
{
foreach (var item in this.Rows)
{
item.RowState = RowState.NoChanging;
item.AcceptChanged();
}
}
/// <summary>
/// 要增加行调用这个方法.
/// </summary>
/// <returns></returns>
public DynamicDataRow NewRow()
{
DynamicDataRow Row = new DynamicDataRow();
Row.RowState = RowState.Inserted;
Row.DataFields = new List<DynamicDataField>();
foreach (var col in this.Columns)
{
DynamicDataField theFld = new DynamicDataField();
theFld.IsDirty = false;
theFld.DataType = col.DataType;
Row.DataFields.Add(theFld);
}
return Row;
}
private DataFieldChanged _DataFieldChanged;
public DataFieldChanged DataFieldChanged
{
get
{
return _DataFieldChanged;
}
set
{
_DataFieldChanged = value;
//设置Field的事件.
foreach (var row in this.Rows)
{
row.SetFieldEvent(value);
}
}
}

}

5)DynamicDataField_1.cs,这个文件放在RIA Service的客户端部分.

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace MEntities
{
/// <summary>
/// 这个部分是DynamicDataField客户端扩展部分，非常关键
/// 主要是实现DynamicDataField几个关键属性的部分方法.
/// 如果是改变前得控制，大家可以实现相关Changing方法。
/// </summary>
public partial class DynamicDataField
{
partial void OnCreated()
{
this.DataMemberChanged = new MyRaiseDataMemberChanged(this.RaiseDataMemberChanged);
}
/// <summary>
///
/// </summary>
partial void OnByteArrayValueChanged()
{
//.....
}

partial void OnDTValueChanged()
{
if (this.DataFieldChanged == null)
{
return;
}
this.DataFieldChanged(this, OldValue, DTValue);
this.OldValue = Value;
}
/// <summary>
/// 值改变时的处理。
/// </summary>
partial void OnStrValueChanged()
{
if (this.DataFieldChanged == null)
{
return;
}
this.DataFieldChanged(this, OldValue, StrValue);
this.OldValue = Value;
}
}
}

6)数据加载时要做处理，代码如下：

theS.GetDynamicDataTable("select * from EmployeeInfo ", op =>
{
if (op.HasError == false)
{
if (op.Value != null)
{
//处理成默认值，追踪变化.
op.Value.AcceptChanged();
}
//DataSource = op.Value.Rows;
DataTable = op.Value;
//挂接事件
DataTable.DataFieldChanged = new DataFieldChanged((fld, oldv, newv) =>
{
MessageBox.Show(newv.ToString());
});
}
else
{
MessageBox.Show(op.ErrorMsg);
}
}, null);

7）数据绑定xaml示意:

<sdk:DataGrid x:Name="CustomGrid" ItemsSource="{Binding Path=DataTable.Rows}" Grid.Row="0" AutoGenerateColumns="False" >
<sdk:DataGrid.Columns>
<sdk:DataGridTextColumn CanUserReorder="True" Binding="{Binding Path=[EmployeeID].Value,Mode=TwoWay}" CanUserResize="True" CanUserSort="True" Width="Auto" />
<sdk:DataGridTextColumn CanUserReorder="True" Binding="{Binding Path=[EmployeeName].StrValue,Mode=TwoWay}" CanUserResize="True" CanUserSort="True" Width="Auto" />
<sdk:DataGridTextColumn CanUserReorder="True" Binding="{Binding Path=[EmployeeDesc].Value,Mode=TwoWay}" CanUserResize="True" CanUserSort="True" Width="Auto" />
<sdk:DataGridTextColumn CanUserReorder="True" Binding="{Binding Path=[EmployeeAge].Value,Mode=TwoWay}" CanUserResize="True" CanUserSort="True" Width="Auto" />
</sdk:DataGrid.Columns>
</sdk:DataGrid>

后记：原来写的时候这个部分没有具体实现，今天补上，这里有个地方要特别声明，Field,Row,Table之间的关系可以定义，但在服务端并不能挂接，否则会发生客户端调用错误，这个在后面的Silverlight 的notfound错误分析博文中有说。同样，事件也无法穿越，因此只能在客户端加载数据的时候进行。