BusyIndicator和DataGrid搭配使用的效果就是当Datagrid加载数据或者提交的时候自动灰掉并出现“Please wait...”进度条，这是一个非常普通的需求，因为从服务器端加载和提交数据谁也不知道需要耗时多久，很多其他的框架比如ExtJS都有很好的支持。在Silverlight中也是很方面的，就是将需要等待载入的控件（这里是DataGrid），作为BusyIndicator 的子控件即可。需要注意的是BusyIndicator自动绑定viewmodel的IsBusy属性怎么做？viewmodel的IsBusy属性如何在加载数据和更新数据的时候进行更新？貌似一个小功能，但要做的完美才行。
前台Xaml：将需要等待载入的控件（这里是DataGrid），作为BusyIndicator 的子控件，IsBusy绑定viewmodel的属性。
< UserControl x:Class ="TestUserControl" xmlns ="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x ="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d ="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc ="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable ="d" d:Height ="Auto" d:Width xmlns:sdk ="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk" xmlns:toolkit ="http://schemas.microsoft.com/winfx/2006/xaml/presentation/toolkit" > toolkit:HeaderedContentControl Name ="headeredContentControl1" Width ="Auto" toolkit:BusyIndicator ="busyIndicator1" IsBusy =" {Binding IsBusy} " displayAfter ="0" BusyContent ="Transferring data..." sdk:DataGrid ItemSource {Binding EntitiesList} AutoGenerateColumns ="False" GridLinesVisibility ="None" HorizontalAlignment ="Stretch" VerticalAlignment BorderThickness ="0,0" SelectionMode ="Single" Name ="dgvRecentUpdated" sdk:DataGrid.Columns sdk:DataGridTextColumn Header ="EntityID" Binding {Binding EntityID} Visibility ="Collapsed" /> ="Entity name" {Binding EntityName} ="120" ="Entity desc" {Binding EntityDesc} ="120" </ sdk:DataGrid toolkit:BusyIndicator toolkit:HeaderedContentControl UserControl >
viewmodel的IsBusy属性设置：当DomainEntity加载和提交的时候自动更新状态
1
public
Boolean IsBusy
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{
3
get
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{
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return
this
._isBusy;
6
}
7
8
private
set
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{
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if
(
this
._isBusy
!=
value)
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{
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this
._isBusy
=
value;
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this
.RaisePropertyChanged(
"
IsBusy
"
);
//
需viewmodel已经实现了INotifyPropertyChanged接口
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}
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}
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}
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private
Boolean _isBusy
=
false
;
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WCF Ria Service的DomainContxt
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private
MyDomainContext _ctx;
22
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protected
MyDomainContext Context
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{
25
26
{
27
if
(_ctx
==
null
)
28
{
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_ctx
=
new
MyDomainContext();
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_ctx.PropertyChanged
+=
new
PropertyChangedEventHandler(_ctx_PropertyChanged);
31
}
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return
_ctx;
34
}
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}
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void
_ctx_PropertyChanged(
object
sender,System.ComponentModel.PropertyChangedEventArgs e)
38
{
39
switch
(e.PropertyName)
40
{
41
case "HasChanges":
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this.HasChanges = _ctx.HasChanges;
43
break;
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case
IsLoading
"
:
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this
.IsBusy
=
_ctx.IsLoading;
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break
;
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IsSubmitting
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this
.IsBusy
=
_ctx.IsSubmitting;
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}
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}
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从WCF Ria Service取数据： Context.Load<T>....
如果你的应用非常简单直接用DomainDataSource，那么就直接把BusyIndicator的IsBusy属性绑定到你的DomainDataSource，会自动改变状态：
sdk:BusyIndicator IsBusy {Binding IsBusy,ElementName=targetDomainDataSource} ... />
自定义BusyIndicator的样式
现在Silverlight的BusyIndicator样式很难看，你可以自定义，比如做一个Firefox的圆形样式：
="SilverlightApplication1.CustomBusyIndicator"
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xmlns:sys
="clr-namespace:System;assembly=mscorlib"
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9
UserControl.Resources
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sys:String
x:Key
="data"
>
M 0,0 L-2,0 L -2,-0 L0,-10 L 2,0 Z
sys:String
11
Storyboard
x:Name
="Storyboard1"
12
DoubleAnimation
BeginTime
="0:0:0"
Duration
="0:0:1"
RepeatBehavior
="Forever"
From
="1"
To
="0.2"
Storyboard.TargetProperty
="(UIElement.Opacity)"
Storyboard.TargetName
="p1"
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="0:0:0.8"
="p2"
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="0:0:0.16"
="p3"
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="0:0:0.24"
="p4"
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="0:0:0.32"
="p5"
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="0:0:0.40"
="p6"
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="0:0:0.48"
="p7"
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="0:0:0.56"
="p8"
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="0:0:0.64"
="p9"
21
="0:0:0.72"
="p10"
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="0:0:0.80"
="p11"
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="0:0:0.88"
="p12"
24
Storyboard
25
26
Grid
="LayoutRoot"
Background
="White"
Margin
="100"
27
Path
="p1"
Data
{Binding Source={StaticResource data}}
stroke
="Gray"
Fill
="Black"
Opacity
="0.2"
28
Path.RenderTransform
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TransformGroup
30
TranslateTransform
Y
="-8"
31
RotateTransform
Angle
="0"
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Path
35
="p2"
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="30"
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="60"
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="90"
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60
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="150"
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77
78
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="180"
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82
83
84
85
86
87
="210"
88
89
90
91
="Black"
92
93
94
95
="240"
96
97
98
99
100
101
102
103
="270"
104
105
106
107
108
109
110
111
="300"
112
113
114
115
116
117
118
119
="330"
120
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122
123
Grid
124
125