CODEWITHSUNDEEP
c#winforms
Itay.B
Itay.B

Reputation: 4121

Test if the Ctrl key is down using C#

I have a form that the user can double click on with the mouse and it will do something. Now I want to be able to know if the user is also holding the Ctrl key down as the user double click on the form.

How can I tell if the user is holding the Ctrl key down?

Upvotes: 69

Views: 84597

Answers (6)

bar-tech
bar-tech

Reputation: 41

This works for me:

 if(Keyboard.IsKeyDown(Key.LeftCtrl))
    {}

And add references to PresentationCore and WindowsBase

Upvotes: 4

Chris Rae
Chris Rae

Reputation: 5675

This isn't really an answer to the question at hand, but I needed to do this in a console application and the detail was a little different.

I had to add references to WindowsBase and PresentationFramework, and at that point I could do:

if (System.Windows.Input.Keyboard.Modifiers == ModifierKeys.Control)
   blah

Just adding this here in case someone else is doing something similar.

Upvotes: 14

Rob
Rob

Reputation: 3381

Just for completeness... ModifierKeys is a static property of Control, so you can test it even when you are not directly in an event handler:

public static bool IsControlDown()
{
    return (Control.ModifierKeys & Keys.Control) == Keys.Control;
}

Upvotes: 42

user1489240
user1489240

Reputation: 31

The same soneone said above, but comparing as different than zero, which should be a little faster and use less instructions on most architectures:

public static bool IsControlDown()
{
    return (Control.ModifierKeys & Keys.Control) != 0;
}

Upvotes: 3

Javed Akram
Javed Akram

Reputation: 15344

Even this also

 private void Control_MouseDoubleClick(object sender, MouseEventArgs e)
    {
        if (ModifierKeys == Keys.Control)
            MessageBox.Show("with CTRL");
    }

Upvotes: 7

Grant Thomas
Grant Thomas

Reputation: 45058

Using .NET 4 you can use something as simple as:

    private void Control_DoubleClick(object sender, EventArgs e)
    {
        if (ModifierKeys.HasFlag(Keys.Control))
        {
            MessageBox.Show("Ctrl is pressed!");
        }
    }

If you're not using .NET 4, then the availability of Enum.HasFlag is revoked, but to achieve the same result in previous versions:

    private void CustomFormControl_DoubleClick(object sender, EventArgs e)
    {
        if ((ModifierKeys & Keys.Control) == Keys.Control)
        {
            MessageBox.Show("Ctrl is pressed!");
        }
    }

Upvotes: 122

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