Member Avatar for OrderChaos

Hello I am working on a simple calculator program for school. I already have all the button clicks working, which is all that was required.

I thought it would be cool if I could get it to where you could use the keyboard for entry and I've done similar things with Visual Basic (which I learned in high school).

I looked online and found the syntax (I'm pretty sure its right) but for some reason it's not sensing a keypress event.

This is the code I have right now, I just want to get the keypress working, I already know how to do the specifics inside the event once it is working.

Oh and I do have keypreview enabled on my form.

private void calculator_KeyPress(object sender, System.Windows.Forms.KeyEventArgs e)
        {
            textBox1.Text = "key pressed";

        }

Thanks in advance for the help and like I said, Its already done as far as the assignment was, I just want to learn how to do this.

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  • Latest Post Latest Post by Ramy Mahrous

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Generated

Good catch by and : the issue is not the idea, it is the wiring and the handler signature. KeyPress uses KeyPressEventArgs, while KeyDown/KeyUp use KeyEventArgs. If your method has KeyEventArgs, it will never be called by the KeyPress event. Also make sure the form is actually subscribed to the event, not just that the method exists. was right about KeyPreview: turn it on so the form sees keys before the focused control. See Microsoft’s docs for the differences and the property behavior: Using keyboard events, Form.KeyPreview, KeyPressEventArgs.

Quick way to wire it up without typing method names:

  • In the designer, select the form, open the Properties window, click the lightning icon, double‑click KeyPress to auto‑generate the handler.
  • Or do it in code in your form’s constructor.
public CalculatorForm() {
    InitializeComponent();
    this.KeyPreview = true;
    this.KeyPress += CalculatorForm_KeyPress;
}

private void CalculatorForm_KeyPress(object sender, KeyPressEventArgs e) {
    // example: append digits typed
    if (char.IsDigit(e.KeyChar)) outputTextBox.AppendText(e.KeyChar.ToString());
}

Tip: not all keys raise KeyPress. Enter, Escape, arrows, and Tab are non‑character keys; handle those in KeyDown and check e.KeyCode. Suppress the default beep when you consume a key by setting e.SuppressKeyPress = true in KeyDown. Example:

private void CalculatorForm_KeyDown(object sender, KeyEventArgs e) {
    if (e.KeyCode == Keys.Enter) { e.SuppressKeyPress = true; equalsButton.PerformClick(); }
}

Details on consuming/suppressing keys are here: Modify keyboard key events.

Recommended Answers

All 11 Replies

Member Avatar for LizR

is that assigned to your forms keypress?

Member Avatar for nelis

Yea something is odd about your code. If that event method was generated by visual studio, why does it have System.Windows.Forms.KeyEventArgs in the parameters definition. To me this makes me think that Windows.Forms isn't in the namespace which would be odd if that code is in the form.

Member Avatar for Ramy Mahrous

From Form properties make Key preview property true, in case your answer to Lizr question is YES.

Member Avatar for OrderChaos

Keypreview is enabled, I think I said that in my original post, but maybe not. Anyway I am using visual c# express to create this and I got the code for the keypress by using MSDN Here: http://msdn.microsoft.com/en-us/library/system.windows.forms.control.keypress.aspx?ppud=4

I couldn't find a way to automatically add in a keypress in visual express. I manually added in the method based upon the msdn example. I am still new to this program, so maybe I just haven't found it yet.

If this isn't what you meant, please let me know and if you know a way to add in the keypress method without manually typing it please let me know.

Member Avatar for LizR

I guess changing from the properties to events in the bottom right (by default) was missing..
So.. Im gonna take an educated guess you didnt tie the event to the method you made??

Member Avatar for OrderChaos

I'm not entirely sure what you mean, considering I am still new to making forms in c# (I was introduced to the language last semester where all we did was command line programs) but I think I know what you mean.

If I understand you correctly there is something I have to do to get the method to be called whenever a key is pressed. If so then you are correct I don't have this.

Also the only thing in the bottom (right or left) is the error list when in code view and the properties window in design view.

Btw thanks for the quick reply.

Member Avatar for ddanbe

When yo are in design view and you press the little button with the lightning symbol on it, in the properties window. You get a list of all available events for the control currently selected. Double click the event you want and you will get into the code view in the eventhandler you just doubleclicked. Type in the code you want to do, it will work. The grungy details of the event handling are taken care of in the in the class.

Member Avatar for OrderChaos

Thanks ddanbe and Lizr its working now!

I didn't realize you could do that. That makes it much easier.

Member Avatar for LizR

cool - please mark it as solved

Member Avatar for Rashakil Fol

cool - please mark it as solved

Why are you so keen on having people mark threads as solved?

Member Avatar for Ramy Mahrous

I frequently ask people to do so, because we can use it as reference or for people need to ask something, may search on them; instead making new one.

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