将CheckBox或RadioButton传递给方法

Question

Currently I am passing my CB and RD to the following methods.

public void objEnabled(System.Windows.Forms.RadioButton x, bool enabled)
    {
        if (x.InvokeRequired)
        {
            BeginInvoke(new MyDelegate(delegate()
            {
                x.Checked = enabled;
            }));
        }
        else
        {
            x.Checked = enabled;
        }
    }

    public void objEnabled(System.Windows.Forms.CheckBox x, bool enabled)
    {
        if (x.InvokeRequired)
        {
            BeginInvoke(new MyDelegate(delegate()
            {
                x.Checked = enabled;
            }));
        }
        else
        {
            x.Checked = enabled;
        }
    }

But I would like to do something like the following.

public void objChecked(Control x, bool enabled)
    {
        if (x.InvokeRequired)
        {
            BeginInvoke(new MyDelegate(delegate()
            {
                x.Checked = enabled;
            }));
        }
        else
        {
            x.Checked = enabled;
        }
    }

I am able to use something similar for changing .Text, .Visible, and .Enable. but .Checked is not part of the Controls class.

Answer 1

The Checked property is not part of interface, so you can't have "common" functionality. They are defined both seperately in RadioButton and CheckBox.

If you would like to treat them as one, you can use dynamic keyword to let the runtime figure it out.

public void objChecked(Control x, bool enabled)
    {
        if(x as RadioButton == null && x as CheckBox == null)
          throw new Exception("Not supported");


        dynamic runtimeObject = (dynamic)x;
        if (x.InvokeRequired)
        {
            BeginInvoke(new MyDelegate(delegate()
            {
                runtimeObject.Checked = enabled;
            }));
        }
        else
        {
            runtimeObject.Checked = enabled;
        }
    }

Answer 2

You'll need to check the type and cast it accordingly.

if (x is System.Windows.Forms.RadioButton)
    (x as System.Windows.Forms.RadioButton).Checked = enabled;
else if (x is System.Windows.Forms.CheckBox)
    (x as System.Windows.Forms.CheckBox).Checked = enabled;

Answer 3

Cast your control x to the type you want: for example, (System.Windows.Forms.RadioButton)x will convert x from control to System.Windows.Forms.RadioButton . Then you should be able to access its checked property.

I don't think System.Windows.Forms has a base class which contains the Checked property, so you'll need to cast your control to a specific implementation which has Checked .

Answer 4

Cast x as a radiobutton

    public void objChecked(Control c, bool enabled)
    {
        RadioButton x = c as RadioButton;
        if(x == null)
            throw new ArgumentException();
        if (x.InvokeRequired)
        {
            BeginInvoke(new MyDelegate(delegate()
            {
                x .Checked = enabled;
            }));
        }
        else
        {
            x.Checked = enabled;
        }
    }

Answer 5

Just as a curiosity, not recommended - other possibility without casting:

    public void objChecked(Control c, bool enabled)
    {
        Expression property
            = Expression.Property(Expression.Constant(c), "Checked");
        var lambda = Expression.Lambda<Action>(
                         Expression.Assign(
                             property,
                             Expression.Constant(enabled)))
                     .Compile();

         if (c.InvokeRequired)
         {
             BeginInvoke(new MyDelegate(delegate()
                 {
                     lambda.Invoke();
                 }));
         }
         else
         {
             lambda.Invoke();
         }
    }

Answer 6

Using Reflection. Will work for any control with a boolean property named Checked .

delegate void MyDelegate(object control, object enabled);
public void objChecked(Control x, bool enabled)
{
    System.Reflection.PropertyInfo pi = x.GetType().GetProperty("Checked");

    if (pi != null && pi.PropertyType == System.Type.GetType("System.Boolean"))
    {
        if (x.InvokeRequired)
            BeginInvoke(new MyDelegate(pi.SetValue), new object[] { x, enabled });
        else
            pi.SetValue(x, enabled);
    }
}