loop through comboboxes

[KlaasVersteeg]

Hi, Ik have a form containing a number of comboboxes, called cmb1, cmb2, etc. I want to loop through these boxes to set their itemlist. I have tried the following code:

for each (Control^ box in this->Controls){
if (box->GetType() == ComboBox::typeid){
box->Items->Clear();
}
}

This works fine, except that I cannot access the combobox's Items property. I can for instance access the Text property, so I think it's strange that the Items property is missing. Does anyone have an idea how to solve this? Thanks!

[Richard Andrew x64]

The reason you can't access the Items property is because you have declared box as a Control and Control doesn't have an Items collection. You would have to declare a new variable as ComboBox and cast box into it:

for each (Control^ box in this->Controls){
if (box->GetType() == ComboBox::typeid){
ComboBox^ combo = (ComboBox^)box;
combo->Items->Clear();
}
}

modified on Friday, June 4, 2010 11:46 AM

[voo doo12]

Have you tried this code

for each(ComboBox^ box in this->Controls)
{
if(box->GetType() == ComboBox::typeid)
{
box->Items->Clear();
}
}

[KlaasVersteeg]

voo doo12, I've tried this, but when I run the program I get an error that says: "Unable to cast object of type 'System.Windows.Forms.Button' to type 'System.Windows.forms.ComboBox'. So it seems that if the program encounters a control which is not a ComboBox it cannot deal with it in this way.

[KlaasVersteeg]

Richard, this makes sense. However, when I compile this code I get: error C2440: 'type cast' : cannot convert from 'System::Windows::Forms::Control ^' to 'System::Windows::Forms::ComboBox' Any idea how to solve this?

[KlaasVersteeg]

Solved! I made a typo in Richard's code (forgot the ^ symbol in the cast part). Now it works, thanks a lot for your help!

[Richard Andrew x64]

Glad to be helpful. :)