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date: Tue, 1 Jul 2008 18:43:58 +0200,
group: microsoft.public.dotnet.framework.windowsforms.controls
back
Databinding not working in test environment, but does work on form
I have a windows form project with a textbox, of which the Text property is
bound to a GUIHandler object's property "ParseString".
(textbox.DataBindings.Add("Text",guihandler,"ParseString")
The GUIHandler impements the INotifyPropertyChanged interface and fires the
PropertyChanged event when its ParseString property is modified.
The textbox on the windows form matches the GUIHandler's ParseString
property nicely. So far so good.
Now I wrote a test routine inside Vstudio's Unittest environment to test
this behaviour (that I already know to work, but there you have it ;-))
[TestMethod]
DisplayTest
{
TextBox box = new TextBox {Text = "Test"};
GUIHandler guih = new GUIHandler { ParseString =
"BeforeClick" };
box.DataBindings.Add("Text", guih, "ParseString");
guih.PropertyChanged+=guih_PropertyChanged;
parsestringchanged.HasFired = false;//parsestringchanged is of
type WaitForEvent.and initialized elsewhere
guih.ParseString = "AfterClick";//this fires the PropertyChanged
event
AwaitEvent(parsestringchanged);
Assert.AreEqual("AfterClick",box.Text);//fails: box.text="Test"
}
private void guih_PropertyChanged(object sender, PropertyChangedEventArgs
e)//Eventhandler
{
parsestringchanged.HasFired = true;
Assert.AreEqual(((GUIHandler)sender).ParseString,"AfterClick");//returns
true
}
private void AwaitEvent(WaitForEvent waiter)
{
bool failed=true;
for (int x = 0; x < 5000;x+=10 )
{
if (waiter.HasFired)
{
failed=false;
break;
Application.DoEvents();
}
}
if(failed)Assert.Fail("Event "+waiter.Name+" did not fire");
}
The test routine creates a Textbox and a GUIHandler and binds the Textbox's
Text property to the GUIHandler's Parsestring property.
I hook up to the GUIHandler's PropertyChanged event and set the HasFired
property of the WaitForEventClass instance parsestringchanged to false.
The WaitForEvent class exposes just one property: HasFired.
I then change the Parsestring property to "AfterClick". This fires the
PropertyChanged event as I can establish that the guih_PropertyChanged
method is executed. The Assertion inside it returns true.
I wait for the event to have been fired using the AwaitEvent method. After
this the TextBox's Text property should read "AfterClick", but it does not!
Q #1:What is wrong?
Q #2: Surely there must be a more elegant way for the test routine to be
notified of the firing of an event in an object that is being tested?
For completeness I give the code for the WaitEvent class below:
private class WaitForEvent
{
private bool hasEventFired;
private readonly object syncRoot;
private string name;
private object param;
public bool HasFired
{
get { return hasEventFired; }
set
{
lock(syncRoot)
{
hasEventFired = value;
}
}
}
public string Name
{
get { return name; }
set { name = value; }
}
public object Param
{
get { return param; }
set
{
lock(syncRoot)
{
param = value;
}
}
}
public WaitForEvent(string eventname)
{
Name = eventname;
syncRoot=new object();
hasEventFired = false;
}
}
date: Tue, 1 Jul 2008 18:43:58 +0200
author: DabblerNL am
RE: Databinding not working in test environment, but does work on form
Hi DabblerNL,
I performed a test based on your description and did see the same thing as
you did.
> Q #1:What is wrong?
The reason why the line of code "ssert.AreEqual("AfterClick",box.Text);"
fails in the DisplayTest test method is that the TextBox instance box is
not shown at all. In fact, when a control is bound to a data source, data
binding engine won't push values from the data source into the control
until the control is shown.
> Q #2: Surely there must be a more elegant way for the test routine to be
notified of the firing of an event in an object that is being tested?
You may subscribe the event of the object to be tested in the test method
to get notified of the firing of the event.
Hope this helps.
If you have any question, please feel free to let me know.
Sincerely,
Linda Liu
Microsoft Online Community Support
Delighting our customers is our #1 priority. We welcome your comments and
suggestions about how we can improve the support we provide to you. Please
feel free to let my manager know what you think of the level of service
provided. You can send feedback directly to my manager at:
msdnmg@microsoft.com.
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date: Wed, 02 Jul 2008 03:43:38 GMT
author: (Linda Liu[MSFT])
Re: Databinding not working in test environment, but does work on form
----- Original Message -----
From: "Linda Liu[MSFT]"
Newsgroups: microsoft.public.dotnet.framework.windowsforms.controls
Sent: Wednesday, July 02, 2008 5:43 AM
Subject: RE: Databinding not working in test environment, but does work on
form
> Hi DabblerNL,
>
> I performed a test based on your description and did see the same thing as
> you did.
>
>> Q #1:What is wrong?
>
> The reason why the line of code "ssert.AreEqual("AfterClick",box.Text);"
> fails in the DisplayTest test method is that the TextBox instance box is
> not shown at all. In fact, when a control is bound to a data source, data
> binding engine won't push values from the data source into the control
> until the control is shown.
>
Thank you! I will adjust the testing routine to see if I can get it to work
with this info.
>> Q #2: Surely there must be a more elegant way for the test routine to be
> notified of the firing of an event in an object that is being tested?
>
> You may subscribe the event of the object to be tested in the test method
> to get notified of the firing of the event.
>
As you see in the code I already did that. The problem is that the MAIN BODY
of the the test method must become aware of the event being fired. so that
it can Assert that a property has changed to the expected value. If I put
the assertion in the method that the event triggers, the assertion will only
be performed IF the event is fired. If it is not, the assertion is never
carried out and it may seem that the test succeeds while actually its result
is unknown. So I would like to have code like:
[TestMethod]
void SomeTest()
{
ObjectToBeTested myTestObject=new ObjectToBetested(some arguments);
myTestObject.ProperyChanged+=DoThis;
DreamedUpWaitHandleObject waithandle;
waithandle.Subscribe(myTestObject.PropertyChanged);
int timeout=10000
WaitHandleResult result=waithandle.WaitForEvent(timeout);
Assert.IsTrue(result==WaitHandleResult.HasFired), "Event did not fire!");
//more testing...
}
void DoThis(object sender, EventArgs e)
{
//some code
}
Is this possible using the System.Threading classes?
date: Thu, 3 Jul 2008 21:31:36 +0200
author: DabblerNL am
Re: Databinding not working in test environment, but does work on form
Hi DabblerNL,
Thank you for your rely!
> I will adjust the testing routine to see if I can get it to work with
this info.
When you run the unit test, the form that contains the TextBox will never
show so data binding will never push data retrieved from data source to the
TextBox in this case and the line of code
"Assert.AreEqual("AfterClick",box.Text);" in the test method will always
fail.
> The problem is that the MAIN BODY of the the test method must become
aware of the event being fired.
For single-threaded WinForm application, events are always handled in the
UI thread. Thus, if a method to be tested fires an event, it is after the
event handler finishes execution that the method goes on its execution.
So in your case, you needn't be aware of the event being fired within the
main body of the test method at all. Just check whether the result is
correct immediately after the line of code that calls the method to be
tested.
Hope this helps.
If you have any question, please feel free to let me know.
Sincerely,
Linda Liu
Microsoft Online Community Support
Delighting our customers is our #1 priority. We welcome your comments and
suggestions about how we can improve the support we provide to you. Please
feel free to let my manager know what you think of the level of service
provided. You can send feedback directly to my manager at:
msdnmg@microsoft.com.
This posting is provided "AS IS" with no warranties, and confers no rights.
date: Fri, 04 Jul 2008 10:34:16 GMT
author: (Linda Liu[MSFT])
Re: Databinding not working in test environment, but does work on form
Thanks! I reference the GUI form directly from within my testing routines
now and have added these lines of code:
form.Visible=false;
form. Show();
The tests are "green".
"Linda Liu[MSFT]" schreef in bericht
news:a5bcKGc3IHA.4056@TK2MSFTNGHUB02.phx.gbl...
> Hi DabblerNL,
>
> Thank you for your rely!
>
>> I will adjust the testing routine to see if I can get it to work with
> this info.
>
> When you run the unit test, the form that contains the TextBox will never
> show so data binding will never push data retrieved from data source to
> the
> TextBox in this case and the line of code
> "Assert.AreEqual("AfterClick",box.Text);" in the test method will always
> fail.
>
>> The problem is that the MAIN BODY of the the test method must become
> aware of the event being fired.
>
> For single-threaded WinForm application, events are always handled in the
> UI thread. Thus, if a method to be tested fires an event, it is after the
> event handler finishes execution that the method goes on its execution.
>
> So in your case, you needn't be aware of the event being fired within the
> main body of the test method at all. Just check whether the result is
> correct immediately after the line of code that calls the method to be
> tested.
>
> Hope this helps.
> If you have any question, please feel free to let me know.
>
> Sincerely,
> Linda Liu
> Microsoft Online Community Support
>
> Delighting our customers is our #1 priority. We welcome your comments and
> suggestions about how we can improve the support we provide to you. Please
> feel free to let my manager know what you think of the level of service
> provided. You can send feedback directly to my manager at:
> msdnmg@microsoft.com.
>
> This posting is provided "AS IS" with no warranties, and confers no
> rights.
>
date: Thu, 10 Jul 2008 20:01:50 +0200
author: DabblerNL am
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