use object in c#.net, like vb.net

Question

I have a method in VB.Net that calls button of form:

Private Sub BUTTON_CAL( _
    ByVal frm As Object, ByVal e As System.Windows.Forms.KeyEventArgs)

    If e.KeyCode = Keys.A AndAlso e.Modifiers = Keys.Control Then
        If frm.AddButton.Enabled = True Then Call frm.AddButton.PerformClick()
        e.SuppressKeyPress = True
    End if
End Sub

I have converted this code into c#

public static void BUTTON_CAL(object frm, System.Windows.Forms.KeyEventArgs e) {
    if(e.KeyCode==Keys.A&&e.Modifiers==Keys.Control) {
        if(frm.AddButton.Enabled==true) {
            frm.AddButton.PerformClick();
        }
        e.SuppressKeyPress=true;
    }
}

in C#.Net I am getting the error

'object' does not contain a definition for AddButton' and no extension method 'AddButton' accepting a first agument of type 'object' could be found(are you missing a using directive or an assembly reference?)

You need to cast frm to it's actual type. Show where you call this method. — Tim Schmelter
– Tim Schmelter, Commented Mar 28, 2013 at 8:02
Side-note: you should really set OPTION STRICT on in VB.NET as well. Also, Call is a redundant statement. — Tim Schmelter
– Tim Schmelter, Commented Mar 28, 2013 at 8:05
Another possibility (which doesn't deserve an answer because it encourages excessive late binding) would be to declare frm as dynamic instead of as object. — stakx - no longer contributing
– stakx - no longer contributing, Commented Mar 28, 2013 at 8:07

Moho · Accepted Answer · 2013-03-28 08:03:54Z

5

Cast 'frm' to the data type you expect it to be (runtime checking if valid is a good idea)

Form form = frm as Form;

if( null == form )
    // error

form.AddButton(...);

answered Mar 28, 2013 at 8:03

Moho

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8 Comments

Jon Skeet Over a year ago

If you're going to throw an error if it's null, just cast instead - it'll be simpler code, and give a clear exception. Also, there's no reason to use if (null == form) rather than if (form == null) in C#. It's not like the typo of if (form = null) would compile.

Moho Over a year ago

Yeah, old habits from C++ die hard ;)

Mandeep Singh Over a year ago

System.Windows.Forms does not contain the definition for 'AddButton' ... How to implement ????

Dmitrii Dovgopolyi Over a year ago

@MandeepSingh "Cast 'frm' to the data type you expect it to be" states the answer. Form is just an example

Dmitrii Dovgopolyi Over a year ago

You can not use even one form if it does not have AddButton property. The solution can be to create in interface IAddingButton{ SomeType AddButton {get; set;} } , inherit all the forms from this interface and cast to it IAddingButton form = frm as IAddingButton;

|

Ken Kin · Accepted Answer · 2013-04-19 11:51:09Z

0

public static void BUTTON_CAL(object sender, KeyEventArgs e) {
    if(sender is Form) {
        var frm=sender as Form;

        if(e.KeyCode==Keys.A && e.Modifiers==Keys.Control) {
            if(frm.AddButton.Enabled)
                frm.AddButton.PerformClick();

            e.SuppressKeyPress=true;
        }
    }
}

The signature of KeyEventHandler is

public delegate void KeyEventHandler(object sender, KeyEventArgs e);

Rather if(SomeBool) than if(SomeBool==true). Don't be unnecessarily complicated.
put someObject as SomeType in a if(someObject is SomeType) would be safe. It seems a little bit redundant, but more readable than compare to null.

edited Apr 19, 2013 at 11:51

answered Mar 28, 2013 at 8:25

Ken Kin

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Comments

Mandeep Singh · Accepted Answer · 2013-04-05 05:26:06Z

-1

Thank you all for giving time to solve the problem I have solved the problem by using below :

public static void BUTTON_CAL(object sender, System.Windows.Forms.KeyEventArgs e) 
{
     var frm = sender as Form;

     if(e.KeyCode==Keys.A&&e.Modifiers==Keys.Control) 
     {  
          if(frm.Controls["AddButton"].Enabled==true)
          {
             ((Button)frm.Controls["AddButton"]).PerformClick();
          }
          e.SuppressKeyPress=true;
     }
}

answered Apr 5, 2013 at 5:26

Mandeep Singh

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2 Comments

Teejay Over a year ago

You really should accept one of the proposed answer, instead of writing your (redundant) one.

bkqc Over a year ago

The original question was how to use Object in C# the same way it can be used in VB. IMHO, this answer is the only one that tries to do some kind of "duck typing" as VB allows so it is not redundant. In fact, other answers were only half complete since they missed that part.

Lefteris E · Accepted Answer · 2013-03-28 09:18:25Z

-2

cast frm to the class name of your form

if (((Form1)frm).AddButton.Enabled == true){
   ((Form1)frm).AddButton.PerformClick();
}

I assume Form1 is the name of your form, and it has a button with name AddButton and that button has the proper access modifier.

edited Mar 28, 2013 at 9:18

answered Mar 28, 2013 at 8:05

Lefteris E

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1 Comment

Dmitrii Dovgopolyi Over a year ago

Forms.Form does not have AddButton field or property. -1

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