- INDEX VB TO NET
- KNOWLEDGE BASE
- EWIS-ISSUES
- ISSUE #2072
ISSUE #2072
1% 2% could not be resolved because it was within the generic namespace 3%.
Description
This occurs when a generic class (like Form class) is used and then a method specific of some classes that inherits from that class, are called, those methods are late binded so, VB6 could resolved (if it exists on the object), but in .Net this is not possible.
Recommendations
Define an Interface and make all the forms that are ussed in those clases implement it. Then use the interface instead of using the generic class (in the example Form Class).
Sample VB6
Form1 Code
PublicSub ObjectMethod()
MsgBox("Form1")
EndSub
Form2 Code
PublicSub ObjectMethod()
MsgBox("Form2")
EndSub
Module Example
PublicSub CallMethodInForm(ByVal F As Form)
F.ObjectMethod()
EndSub
PublicSub Test()
Dim F1 AsNew Form1
Dim F2 AsNew Form2
CallMethodInForm(F1)
CallMethodInForm(F2)
EndSub
Target VB.NET
Form1 Code
Inherits System.Windows.Forms.Form
PublicSub ObjectMethod()
MessageBox.Show("Form1", Application.ProductName)
EndSub
Form2 Code
Inherits System.Windows.Forms.Form
PublicSub ObjectMethod()
MessageBox.Show("Form2", Application.ProductName)
EndSub
Module Example
PublicSub CallMethodInForm(ByVal F As Form)
'UPGRADE_ISSUE: (2072) Control ObjectMethod could not be resolved because it was within the generic namespace Form.
F.ObjectMethod()
EndSub
PublicSub Test()
Dim F1 AsNew Form1
'UPGRADE_ISSUE: (2068) Form2 object was not upgraded.
Dim F2 AsNew Form2
CallMethodInForm(F1)
'UPGRADE_WARNING: (1068) F2 of type Form2 is being forced to VB.Form.
CallMethodInForm(F2)
EndSub
Expected VB.NET
Add an Interface
PublicInterface FormInterface
Sub ObjectMethod()
EndInterface
Form1 Code
Inherits System.Windows.Forms.Form
Implements FormInterface
PublicSub ObjectMethod() Implements FormInterface.ObjectMethod
MessageBox.Show("Form1", Application.ProductName)
EndSub
Form2 Code
Inherits System.Windows.Forms.Form
Implements FormInterface
PublicSub ObjectMethod() Implements FormInterface.ObjectMethod
MessageBox.Show("Form2", Application.ProductName)
EndSub
Module Example
PublicSub CallMethodInForm(ByVal F As FormInterface)
F.ObjectMethod()
EndSub
PublicSub Test()
Dim F1 AsNew Form1
Dim F2 AsNew Form2
CallMethodInForm(F1)
CallMethodInForm(F2)
EndSub
Target C#
Form1 Code
internalpartialclassForm1
: System.Windows.Forms.Form
{
publicvoid ObjectMethod()
{
MessageBox.Show("Form1", Application.ProductName);
}
}
Form2 Code
internalpartialclassForm2
: System.Windows.Forms.Form
{
publicvoid ObjectMethod()
{
MessageBox.Show("Form2", Application.ProductName);
}
}
Module Example
staticpublicvoid CallMethodInForm( Form F)
{
//UPGRADE_ISSUE: (2072) Control ObjectMethod could not be resolved because it was within the generic namespace Form.
F.ObjectMethod();
}
staticpublicvoid Test()
{
Form1 F1 = newForm1();
Form2 F2 = newForm2();
CallMethodInForm(F1);
CallMethodInForm(F2);
}
Expected C#
Add an Interface
interfaceFormInterface
{
void ObjectMethod();
}
Form1 Code
internalpartialclassForm1
: System.Windows.Forms.Form, FormInterface
{
publicvoid ObjectMethod()
{
MessageBox.Show("Form1", Application.ProductName);
}
}
Form2 Code
internalpartialclassForm2
: System.Windows.Forms.Form, FormInterface
{
publicvoid ObjectMethod()
{
MessageBox.Show("Form2", Application.ProductName);
}
}
Module Example
staticpublicvoid CallMethodInForm(FormInterface F)
{
F.ObjectMethod();
}
staticpublicvoid Test()
{
Form1 F1 = newForm1();
Form2 F2 = newForm2();
CallMethodInForm(F1);
CallMethodInForm(F2);
}
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