Declare and Define an Object Dynamically

Samantha Kliff

Hi,
I have the following situation, can anybody help me in that?

Following is a "pseudo" code of what I want to do in VB or C# using VS.NET 2005:

In my main form I have the following
'Code Begins
Dim vCurrentForm As Form

Private Sub CallCurrentForm (ByVal pForm as String)
   If vCurrentForm Is Nothing OrElse vCurrentForm.IsDisposed Then
      vCurrentForm = <# New pForm #>
      vCurrentForm.MdiParent = Me
   ElseIf Not TypeOf vCurrentForm Is <# pForm #> Then
      vCurrentForm.Close()
      vCurrentForm = <# New pForm #>
      vCurrentForm.MdiParent = Me
   End If
   vCurrentForm.Show()
End Sub
'Code Ends

Where I am calling 'CallCurrentForm' everywhere in my menu just by passing the proper form name as a string
example: CallCurrentForm("AddNewAccount")

My problem is how to do the code between <# ... #>

Thanks

3 Replies

Know the answer? Post it — somebody with the same question will find it here.

Danatas Gervi17y ago

I miss If problem ....

 If (cCurrForm.GetType.Name <> pForm) Then
   cCurrForm.Close
   cCurrForm = DirectCast(Activator.CreateInstance(Assembly.GetExecutingAssembly.GetType(pForm)), Form) 
End If

Pay atension -

cCurrForm  - must be base class for pForm  and previos form. In common case, it may be System.Windows.Form.

But if you want more, than simple showing, you should or use a casting to needed form, or use base class or interface.

Master Billa17y ago
Hi

Here code for you

public static Object GetReferenceFromClass(string AssemblyName, string ClassName, object[] args)

        {

            Assembly assembly = Assembly.LoadFrom(AssemblyName);

            foreach (Type type in assembly.GetTypes())

            {

                if (type.IsClass == true)

                {

                    if (type.FullName.EndsWith("." + ClassName))

                    {

                        ConstructorInfo[] con = type.GetConstructors();

                        foreach (ConstructorInfo construtor in con)

                        {

                            if (construtor.GetParameters().Length == args.Length)

                            {

                                return construtor.Invoke(args);

                            }

                        }

                    }

                }

            }



            throw (new System.Exception("could not create instanace----->" + ClassName));

        }

Thank you
Danatas Gervi17y ago
You should use reflection metods:

Dim cCurrForm As Form = DirectCast(Activator.CreateInstance(Assembly.GetExecutingAssembly.GetType(pForm)), Form)