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//-----------------------------------------------------------------------------
// Copyright (c) Microsoft Corporation. All rights reserved.
//-----------------------------------------------------------------------------
namespace System.Activities.Statements
{
using System.Activities;
using System.Activities.Expressions;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq.Expressions;
using System.Runtime;
using System.Runtime.Collections;
using System.Windows.Markup;
using SA = System.Activities;
[ContentProperty("Body")]
public sealed class DoWhile : NativeActivity
{
CompletionCallback onBodyComplete;
CompletionCallback<bool> onConditionComplete;
Collection<Variable> variables;
public DoWhile()
: base()
{
}
public DoWhile(Expression<Func<ActivityContext, bool>> condition)
: this()
{
if (condition == null)
{
throw SA.FxTrace.Exception.ArgumentNull("condition");
}
this.Condition = new LambdaValue<bool>(condition);
}
public DoWhile(Activity<bool> condition)
: this()
{
if (condition == null)
{
throw SA.FxTrace.Exception.ArgumentNull("condition");
}
this.Condition = condition;
}
public Collection<Variable> Variables
{
get
{
if (this.variables == null)
{
this.variables = new ValidatingCollection<Variable>
{
// disallow null values
OnAddValidationCallback = item =>
{
if (item == null)
{
throw SA.FxTrace.Exception.ArgumentNull("item");
}
}
};
}
return this.variables;
}
}
[DefaultValue(null)]
[DependsOn("Variables")]
public Activity<bool> Condition
{
get;
set;
}
[DefaultValue(null)]
[DependsOn("Condition")]
public Activity Body
{
get;
set;
}
protected override void OnCreateDynamicUpdateMap(DynamicUpdate.NativeActivityUpdateMapMetadata metadata, Activity originalActivity)
{
metadata.AllowUpdateInsideThisActivity();
}
protected override void CacheMetadata(NativeActivityMetadata metadata)
{
metadata.SetVariablesCollection(this.Variables);
if (this.Condition == null)
{
metadata.AddValidationError(SA.SR.DoWhileRequiresCondition(this.DisplayName));
}
else
{
metadata.AddChild(this.Condition);
}
metadata.AddChild(this.Body);
}
protected override void Execute(NativeActivityContext context)
{
// initial logic is the same as when the condition completes with true
OnConditionComplete(context, null, true);
}
void ScheduleCondition(NativeActivityContext context)
{
Fx.Assert(this.Condition != null, "validated in OnOpen");
if (this.onConditionComplete == null)
{
this.onConditionComplete = new CompletionCallback<bool>(OnConditionComplete);
}
context.ScheduleActivity(this.Condition, this.onConditionComplete);
}
void OnConditionComplete(NativeActivityContext context, ActivityInstance completedInstance, bool result)
{
if (result)
{
if (this.Body != null)
{
if (this.onBodyComplete == null)
{
this.onBodyComplete = new CompletionCallback(OnBodyComplete);
}
context.ScheduleActivity(this.Body, this.onBodyComplete);
}
else
{
ScheduleCondition(context);
}
}
}
void OnBodyComplete(NativeActivityContext context, ActivityInstance completedInstance)
{
ScheduleCondition(context);
}
}
}
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