e.keychar 返回 ascii 值。 我如何获得 char/int 值？

Question

Iam trying to get the interget value from e.KeyChar but it just gives me the ascii value.

To make it short.

int[] row = {1,2,3};


        private void Inputnr1box_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (!char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar))
            {
                e.Handled = true; 
            }
            else if (row.Contains(e.KeyChar) ) { MessageBox.Show("Well done boys");

            }
            else { MessageBox.Show("Fail!"); }
        }

If i try to change one value in my array to say 49 and send "1" everything is fine.

The problem origins from a larger set of textboxes where the user can put numeric values, but is not allowed to enter duplicate values. I planed to save the values in an integer array and then use contains to see if it already have been entered once.

Answer 1

You can do the following to identify whether the pressed key is an Number and handle if the number is not there.

    List<int> row = new List<int>();

    private void Inputnr1box_KeyPress(object sender, KeyPressEventArgs e)
    {
        if (!char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar))
        {
            e.Handled = true; // Not a DIGIT
        }
        else
        {
            // Else test for existence
            int number;
            if (Int32.TryParse(e.KeyChar.ToString(), out number))
            {
                if (row.Contains(number))
                {
                    e.Handled = true;  // Already exists
                }
                else
                {
                    row.Add(number);
                }
            }
        }
    }

Answer 2

Try this, the game_KeyPress and game_KeyDown methods detect the pressed keys. The control keys can be found in the Keys enumeration of windows forms, a trick you can do is put "switch (Keys)" and the automatic autocomplete of Visual studio 2019 will show all the enumerations included in Keys. Not all pressed keys are detected by the game_KeyPress method so we use game_KeyDown to detect arrows. Some keys have their specific events.

    private void game_KeyPress(object sender, KeyPressEventArgs e)
    {
        int iKey = 0;
        char cKey = ' ';
        string sKey = " ";

        if (char.IsControl(e.KeyChar) || !char.IsDigit(e.KeyChar))
        {
            if (char.IsControl(e.KeyChar)) // Special key
            {
                if (e.KeyChar == (char)Keys.Back)
                {
                    sKey = Keys.Back.ToString(); // to save value
                    MessageBox.Show(sKey, "information", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }

                if (e.KeyChar == (char)Keys.Tab)
                    MessageBox.Show(Keys.Tab.ToString(), "information", MessageBoxButtons.OK, MessageBoxIcon.Information);
                if (e.KeyChar == (char)Keys.Enter)
                    MessageBox.Show(Keys.Enter.ToString(), "information", MessageBoxButtons.OK, MessageBoxIcon.Information);
                if (e.KeyChar == (char)Keys.Space)
                    MessageBox.Show(Keys.Space.ToString(), "information", MessageBoxButtons.OK, MessageBoxIcon.Information);

            }
            else // Normal key
            {
                cKey = e.KeyChar; // to save value
                MessageBox.Show(cKey.ToString(), "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
        }
        else // Number
        {
            iKey = Convert.ToInt32(char.GetNumericValue(e.KeyChar)); // to save value
            MessageBox.Show(iKey.ToString(), "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
        }

        e.Handled = true; // e.handled is a property then assigned to true, it deletes the character from the keychar property value 
    }

    private void game_KeyDown(object sender, KeyEventArgs e)
    {
        if (e.KeyCode == Keys.Down) 
            MessageBox.Show(Keys.Down.ToString(), "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);            

        if (e.KeyCode == Keys.Up)
            MessageBox.Show(Keys.Up.ToString(), "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);

        if (e.KeyCode == Keys.Left)
            MessageBox.Show(Keys.Left.ToString(), "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);

        if (e.KeyCode == Keys.Right)
            MessageBox.Show(Keys.Right.ToString(), "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);

        e.Handled = true; // e.handled is a property then assigned to true, it deletes the character from the keychar property value
    }