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Type.GetType with two projects

P: n/a
I have two projects in one solution. One is called Frontier and holds
all my base user controls, classes, etc. that are used over multiple
applications. The second is my application project (OCFU) which holds
the forms and code that the users run. I need to instantiate a new
form only given the form's name in a string. In the calling form in
the OCFU project I used the following code:

Dim objNewForm As Object =
Activator.CreateInstance(Type.GetType(myApplicatio nName & "." &
FormToOpen))
Dim frm As FrontierForm = DirectCast(objNewForm, FrontierForm)

The "myApplicationName & "." & FormToOpen" code fully qualifies the
form. The myApplicationName is a global variable of the application
name, in this case OCFU. It works when the code is in a form from
within the OCFU project.

I then copied this code to a class in the Frontier project so that it
is reusable by multiple applications. Then I commented out the code in
the OCFU form. Now it doesn't work. The Type.GetType procedure
returns Nothing. It's as if it cannot find the OCFU project and the
form within it. Am I missing additional qualification?

Feb 8 '06 #1
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6 Replies


P: n/a
Did you reference the other project?

T

Paul wrote:
I have two projects in one solution. One is called Frontier and holds
all my base user controls, classes, etc. that are used over multiple
applications. The second is my application project (OCFU) which holds
the forms and code that the users run. I need to instantiate a new
form only given the form's name in a string. In the calling form in
the OCFU project I used the following code:

Dim objNewForm As Object =
Activator.CreateInstance(Type.GetType(myApplicati onName & "." &
FormToOpen))
Dim frm As FrontierForm = DirectCast(objNewForm, FrontierForm)

The "myApplicationName & "." & FormToOpen" code fully qualifies the
form. The myApplicationName is a global variable of the application
name, in this case OCFU. It works when the code is in a form from
within the OCFU project.

I then copied this code to a class in the Frontier project so that it
is reusable by multiple applications. Then I commented out the code in
the OCFU form. Now it doesn't work. The Type.GetType procedure
returns Nothing. It's as if it cannot find the OCFU project and the
form within it. Am I missing additional qualification?

Feb 9 '06 #2

P: n/a
TSI
I think the error is here
GetType(myApplicationName & "." &
FormToOpen))

cuz you try to pass a String value instead of you passing an Object .

Feb 9 '06 #3

P: n/a
Paul,

I see this the last weeks more and more in this newsgroup and I really don't
understand it.

What is your code better than

Dim myform as new MySecondProject.Form1 (the name from the form as you use
now in a string)

Can you enlighten me?

A second question is what do you mean by FormToOpen is that a term from old
Basic? An existing Form object can be showed or an Form object can be
instanced from a Class.

I have the idea that you have this all from VBA and create something
terrible difficult for a simple problem.

However, just my idea.

Cor
Feb 9 '06 #4

P: n/a
Thanks for the responses. Let me try to explain further...

tomb: Did you reference the other project?

In the code "Type.GetType(myApplicationName & "." &
FormToOpen)" the variable myApplicationName is a global variable. The
value of the variable is the name of the project (assembly, they are
the same) that the form I want to open is housed in.

TSI: I think the error is here

No, that is not correct. If you just code "GetType(???)" the parameter
for the GetType procedure is an object. That is what you are referring
to. However, the Type.GetType function accepts a string as a
parameter.

Cor: I really don't understand it.

I'm converting an old application. The old application dynamically
generates a menuing system on the form through a table. So when the
user presses a button the form they want to open will vary. The form
name is read from a table and then needs to be opened. That is why I
am doing this. I have multiple applications that do this and so need
to get it to work.

Cor: what do you mean by FormToOpen

The "FormToOpen" is a passed parameter. The code I posted is contained
within a Sub that is passed "FormToOpen As String". Below is the
entire Sub (except for the exception handling code). You don't
actually need it.

Public Sub OpenForm(ByVal FormToOpen As String, Optional ByVal View
As AcView = AcView.acViewNormal, Optional ByVal FilterName As Object =
"", Optional ByVal WhereCondition As Object = "", Optional ByVal
DataMode As AcFormOpenDataMode =
AcFormOpenDataMode.acFormPropertySettings, Optional ByVal WindowMode As
AcWindowMode = AcWindowMode.acWindowNormal, Optional ByVal OpenArgs As
Object = "")
Try
Dim objNewForm As Object =
Activator.CreateInstance(Type.GetType(myApplicatio nName & "." &
FormToOpen))
Dim frm As FrontierForm = DirectCast(objNewForm,
FrontierForm)
RaiseEvent OpenForm_Event(frm, View, FilterName,
WhereCondition, DataMode, WindowMode, OpenArgs)
Catch ex As Exception
... execption handling code (not important)
End Try
End Sub

This Sub is contained within a Class that is in the Frontier project.
Frontier is a Class project that will be used by multiple other
application (Window) projects. That is why I need it here.

I am positive that the problem is with the code
"Type.GetType(myApplicationName & "." & FormToOpen)". It returns
Nothing. I can see it when I am debugging the program. The reason is
because it cannot find the form. I just need to know how to qualify it
more. I'm just not sure how to do it, if it's even possible.

My basic question is, "From one project, how to you fully qualify a
reference to a form in a second project when both projects are in the
same solution?"

Feb 9 '06 #5

P: n/a
Paul,

Cor: what do you mean by FormToOpen

Public Sub OpenForm(ByVal FormToOpen As String, Optional ByVal View
As AcView = AcView.acViewNormal, Optional ByVal FilterName As Object =
"", Optional ByVal WhereCondition As Object = "", Optional ByVal
DataMode As AcFormOpenDataMode =
AcFormOpenDataMode.acFormPropertySettings, Optional ByVal WindowMode As
AcWindowMode = AcWindowMode.acWindowNormal, Optional ByVal OpenArgs As
Object = "")
Try
Dim objNewForm As Object =
Activator.CreateInstance(Type.GetType(myApplicatio nName & "." &
FormToOpen))
Dim frm As FrontierForm = DirectCast(objNewForm,
FrontierForm)
RaiseEvent OpenForm_Event(frm, View, FilterName,
WhereCondition, DataMode, WindowMode, OpenArgs)
Catch ex As Exception
... execption handling code (not important)
End Try
End Sub

This is exactly as I thought, I would refactor it in your case, than you
will see your program will be look much nicer.

What is wrong with setting all your possible forms in an hashtable and tell
than what class you want depending on the string, you do the show and
setting all those properties than of course in the class that is calling it,
and don't make this kind of modulair code.

I thought this because in past the term Open a form was used, what is a long
time ago when the distinct in VB between a class and an object was messed up
and the difference was not good to see (this especialy with the form,
therefore some of us are not so lucky with the from past reinvented "my"
class).

Just my thought,

Cor
Feb 9 '06 #6

P: n/a
Thanks again Cor for the quick response.

I believe the scenario I am describing is not possible. I created a
small example to test it. I created a simple two form project called
WindowsApplication1. Its forms are Form1 and Form2 I created a second
project called ClassLibrary1 which has one class called Class1. Both
are contained within one solution.

The WindowsApplication1 library has a project reference to
ClassLibrary1. Form1 instantiates an object called c as Class1. I
then tried the following code in Class1:

Public Sub DoSomething()
dim frm as New ???
End Sub

I was going to hard-code the qualified reference to the
WindowsApplication1.Form2. But ClassLibrary1 does not have a reference
to WindowsApplication1. When I tried to add the reference to
ClassLibrary1, it generated an error about circular references.

This makes sense and what I'm wanting to do is not possible. So, I'll
generate the forms within the applications project.

Thanks for the help!

Feb 9 '06 #7

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