如何从另一个窗体（类）中调用要在按钮内使用的comboBox

Question

I want to call a some combo-box items so i can make an if /else statements and output a form.The combo-box items are out side of my class(Form) how can i access them i tried this(below) but the error says does not exist in the current context.I also changed it the method from private to public

public void buttonFinish_Click(object sender, EventArgs e)
{           
    if(comboBoxD.Text == "Alphabet" && comboBoxType.Text == "Numbers")
    {

    }
}

Answer 1

Send ComboBox from form1 to form2 using constructor. Here is example:

Form1 Class:

public partial class Form1 : Form
{        
   public Form1()
   {
        InitializeComponent();
   }

   private void Form1_Load(object sender, EventArgs e)
   {
       Form2 f2 = new Form2(comboBox1, comboBox2);
       f2.Show();
   }
}

Form2 Class:

public partial class Form2 : Form
{ 
   ComboBox comboBoxD; 
   ComboBox comboBoxType;

   public Form2(ComboBox cb, ComboBox cbType)
   {
        InitializeComponent();
        comboBoxD = cb;
        comboBoxType = cbType;
   }

   private void Form2_Load(object sender, EventArgs e)
   {

   }

   protected void buttonFinish_Click(object sender, EventArgs e)
   {           
        if(comboBoxD.Text == "Alphabet" && comboBoxType.Text == "Numbers")
        {

        }
   }
}

UPDATE :

Here is another approach for accessing controls present in another form.

Default Modifiers of every control is private . For controls you want to access from another form you have change Modifiers property as Public .

Form1 Class:

public partial class Form1 : Form
{        
   public Form1()
   {
        InitializeComponent();
   }

   private void Form1_Load(object sender, EventArgs e)
   {
       Form2 f2 = new Form2(this);
       f2.Show();
   }
}

Form2 Class:

public partial class Form2 : Form
{
    private Form1 f1;
    public Form2(Form1 f)
    {
      InitializeComponent();
      f1 = f;
    }

    protected void buttonFinish_Click(object sender, EventArgs e)
    {           
        if(f1.comboBoxD.Text == "Alphabet" && f1.comboBoxType.Text == "Numbers")
        {

        }
    }
}

Answer 2

You can write a public method in your ComboBox 's class and then call it from where you have instance of that form.

like this:

in your main form:

  using (var modal = new MyModal())
  {
            modal.ShowDialog();
            modal.getSomething();
  }

in your modal:

  public string getSomething()
  {
       return yourComboBox.Text;
  }     

Answer 3

This is because your ComboBox is only available in the codebehind file of your Form.

One solution would be to store a reference to your combobox as a property in your codebehind.

like this:

public ComboBox myCmbBox { get; private set; }

and access it in the codebehind of form2.