Reference a form object via reflection?

[nam23]

Hi,

I'd like to create a List containing all the checkboxes on a form. The
thing is, I don't know how many checkboxes there might be. I thought
perhaps I could use reflection to look at all of the fields on the
form; if a given field is of type System.Windows.Forms.Checkbox, then
I'd add it to the List. But the following code isn't working.

....
public formConstructor()
{
List<CheckBox> checkBoxesOnForm = new List<CheckBox>();
InitializeComponents();
FieldInfo[] formFields = this.GetType().GetFields();
int numberOfFields = formFields.getLength(0);
For (int i = 0; i < numberOfFields; i++)
{
if (formFields.FieldType is CheckBox)
{
//add the checkbox to the List somehow...???
//The following line doesn't work but was a wild guess
checkBoxesOnForm.Add(((Checkbox)formFields.GetValue()))
}
}
}
....

The above code has two main problems:
- The compiler warns that FieldType won't ever be of type CheckBox
- I don't know how to grab a reference to the checkbox from the
FieldInfo array

Anyone have any ideas? Thanks very much...

Neil McQuarrie

 

[Brendan Green]

Might be easier to loop thorough all controls contained in Form.Controls.

Example of what I've recently done:

foreach (Control c in this.Controls)
{
if (c is CheckBox)
{
CheckBox chk = c as CheckBox;
int tag = Convert.ToInt32(chk.Tag);

if ( (freq & tag) == tag)
{
chk.Checked = true;
}
else
{
chk.Checked = false;
}
}
}

 

[nam23]

Great! I think that will do the trick. Much appreciated...

Neil

Might be easier to loop thorough all controls contained in Form.Controls.

Example of what I've recently done:

foreach (Control c in this.Controls)
{
if (c is CheckBox)
{
CheckBox chk = c as CheckBox;
int tag = Convert.ToInt32(chk.Tag);

if ( (freq & tag) == tag)
{
chk.Checked = true;
}
else
{
chk.Checked = false;
}
}
}

Hi,

I'd like to create a List containing all the checkboxes on a form. The
thing is, I don't know how many checkboxes there might be. I thought
perhaps I could use reflection to look at all of the fields on the
form; if a given field is of type System.Windows.Forms.Checkbox, then
I'd add it to the List. But the following code isn't working.

...
public formConstructor()
{
List<CheckBox> checkBoxesOnForm = new List<CheckBox>();
InitializeComponents();
FieldInfo[] formFields = this.GetType().GetFields();
int numberOfFields = formFields.getLength(0);
For (int i = 0; i < numberOfFields; i++)
{
if (formFields.FieldType is CheckBox)
{
//add the checkbox to the List somehow...???
//The following line doesn't work but was a wild guess
checkBoxesOnForm.Add(((Checkbox)formFields.GetValue()))
}
}
}
...

The above code has two main problems:
- The compiler warns that FieldType won't ever be of type CheckBox
- I don't know how to grab a reference to the checkbox from the
FieldInfo array

Anyone have any ideas? Thanks very much...

Neil McQuarrie

 

[Piotr Dobrowolski]

Hello (e-mail address removed),

Hi,

I'd like to create a List containing all the checkboxes on a form.
The thing is, I don't know how many checkboxes there might be. I
thought perhaps I could use reflection to look at all of the fields on
the form; if a given field is of type System.Windows.Forms.Checkbox,
then I'd add it to the List. But the following code isn't working.

...
public formConstructor()
{
List<CheckBox> checkBoxesOnForm = new List<CheckBox>();
InitializeComponents();
FieldInfo[] formFields = this.GetType().GetFields();
int numberOfFields = formFields.getLength(0);
For (int i = 0; i < numberOfFields; i++)
{
if (formFields.FieldType is CheckBox)
{
//add the checkbox to the List somehow...???
//The following line doesn't work but was a wild guess
checkBoxesOnForm.Add(((Checkbox)formFields.GetValue()))
}
}
}
...

The above code has two main problems:
- The compiler warns that FieldType won't ever be of type CheckBox
- I don't know how to grab a reference to the checkbox from the
FieldInfo array
Anyone have any ideas? Thanks very much...

[PD] The solution you received from Brendan is much better than using reflection,
but just for your information:
- FieldType won't ever be of type CheckBox, because it's of type Type
You can write desired condition like this: FieldType.IsAssignableFrom(typeof(CheckBox)).
- To grab a reference you should call formFields.GetValue(this)
- By default fields created by the designer are private so GetFields() won't
return them. Use GetFields with BindingFlags.NonPublic
- You should be aware that not all controls that are on the form must be
referenced by form fields.

Piotr Dobrowolski
Piotr.Dobrowolski_usun_gmail.com