我正在制作类似于“彼得答案”的东西。它被称为“Adrian Answers”，因为这是我的名字。但这无关紧要。这个问题之前已经得到了回答，但我无法弄清楚如何将这个应用到我的情况中。我需要退格键才能无法按下。如果你按住它，它应该只在程序中注册一次，但不能在此之后的任何时间注册。顺便说一句，我想在textBox1中使用此功能。这是Peter Answers的参考。 http://www.peteranswers.com/
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace PeterAnswers
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
bool secret = false;
string answer;
string normal = "Adrian, please answer my question:";
int i = 0;
bool secret2 = false;
private void textBox1_KeyPress(object sender, KeyEventArgs e)
{
if (e.KeyData == Keys.OemPeriod && textBox1.Text.Length == 0)
{
i = 0;
e.SuppressKeyPress = true;
secret = true;
textBox1.Text += normal[i];
textBox1.Select(textBox1.Text.Length, 0);
i++;
answer = null;
}
else if (e.KeyData == Keys.OemPeriod && secret == true)
{
e.SuppressKeyPress = true;
textBox1.Text += normal[i];
secret = false;
textBox1.Select(textBox1.Text.Length, 0);
secret2 = true;
}
else if(e.KeyData != Keys.OemPeriod && secret == true && e.KeyData != Keys.Back && Control.ModifierKeys != Keys.Shift && e.KeyData != Keys.Space)
{
e.SuppressKeyPress = true;
answer += e.KeyData;
textBox1.Text += normal[i];
textBox1.Select(textBox1.Text.Length, 0);
i++;
}
else if (e.KeyData == Keys.Back && secret == true)
{
string petition = textBox1.Text;
if (petition.Length != 0)
{
if (petition.Length > 1)
{
petition = petition.Remove(petition.Length - 1);
answer = answer.Remove(answer.Length - 1);
i--;
}
else if (petition.Length == 1)
{
petition = petition.Remove(petition.Length - 1);
i--;
secret = false;
secret2 = false;
answer = null;
}
else if (answer.Length > 0)
{
answer = answer.Remove(answer.Length - 1);
}
else if (answer.Length <= 0)
{
answer = null;
}
}
}
else if (e.KeyData == Keys.Space && secret == true)
{
e.SuppressKeyPress = true;
answer += " ";
textBox1.Text += normal[i];
textBox1.Select(textBox1.Text.Length, 0);
i++;
}
else if (Control.ModifierKeys == Keys.Shift && secret == true)
{
e.SuppressKeyPress = true;
textBox1.Select(textBox1.Text.Length, 0);
}
}
private void button1_Click(object sender, EventArgs e)
{
if (answer != null && secret2 == true)
{
answerLabel.Visible = true;
answer = System.Threading.Thread.CurrentThread.CurrentCulture.TextInfo.ToTitleCase(answer.ToLower());
answerLabel.Text += " " + answer;
}
else
{
Random rand = new Random();
switch(rand.Next(0, 4))
{
case 1:
answerLabel.Visible = true;
answerLabel.Text += " Sorry, cannot compute answer at the moment. Please try again later.";
break;
case 2:
answerLabel.Visible = true;
answerLabel.Text += " Something seems to be blocking my mental powers...";
break;
case 3:
answerLabel.Visible = true;
answerLabel.Text += " No answer.";
break;
case 4:
answerLabel.Visible = true;
answerLabel.Text += " I find your lack of faith disturbing...";
break;
}
}
secret = false;
secret2 = false;
}
private void button2_Click(object sender, EventArgs e)
{
i = 0;
answerLabel.Visible = false;
textBox1.Clear();
textBox2.Clear();
answer = null;
secret = false;
secret2 = false;
answerLabel.Text = "Answer:";
}
}
}
答案 0 :(得分：5)
使用KeyDown，KeyUp和Boolean标记的组合：
private Boolean _backspace = false;
private void textBox1_KeyDown(Object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Back)
{
e.SuppressKeyPress = _backspace;
e.Handled = _backspace;
_backspace = true;
}
}
private void textBox1_KeyUp(Object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Back)
_backspace = false;
}
该标志只是帮助处理程序知道密钥何时被保持以及何时再次允许它。
答案 1 :(得分：1)
Don的答案应该可以正常工作（我赞成它）。作为其答案的扩展，您还可以将其退格逻辑抽象为新的TextBox控件：
public class EnhancedTextBox : TextBox
{
private Boolean _backspace = false;
public EnhancedTextBox()
{
KeyDown += new KeyEventHandler(EnhancedTextBox_KeyDown);
KeyUp += new KeyEventHandler(EnhancedTextBox_KeyUp);
}
void EnhancedTextBox_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Back)
_backspace = false;
}
void EnhancedTextBox_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Back)
{
e.SuppressKeyPress = _backspace;
e.Handled = _backspace;
_backspace = true;
}
}
}
所以，你要用它替换textBox1：
private void InitializeComponent()
{
this.textBox1 = new EnhancedTextBox();
...
}
然后将现有逻辑从KeyPress移至KeyUp：
private void textBox1_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyData == Keys.OemPeriod && textBox1.Text.Length == 0)
{
i = 0;
e.SuppressKeyPress = true;
secret = true;
textBox1.Text += normal[i];
textBox1.Select(textBox1.Text.Length, 0);
i++;
answer = null;
}
else if (e.KeyData == Keys.OemPeriod && secret == true)
{
e.SuppressKeyPress = true;
textBox1.Text += normal[i];
secret = false;
textBox1.Select(textBox1.Text.Length, 0);
secret2 = true;
}
else if(e.KeyData != Keys.OemPeriod && secret == true && e.KeyData != Keys.Back && Control.ModifierKeys != Keys.Shift && e.KeyData != Keys.Space)
{
e.SuppressKeyPress = true;
answer += e.KeyData;
textBox1.Text += normal[i];
textBox1.Select(textBox1.Text.Length, 0);
i++;
}
else if (e.KeyData == Keys.Back && secret == true)
{
string petition = textBox1.Text;
if (petition.Length != 0)
{
if (petition.Length > 1)
{
petition = petition.Remove(petition.Length - 1);
answer = answer.Remove(answer.Length - 1);
i--;
}
else if (petition.Length == 1)
{
petition = petition.Remove(petition.Length - 1);
i--;
secret = false;
secret2 = false;
answer = null;
}
else if (answer.Length > 0)
{
answer = answer.Remove(answer.Length - 1);
}
else if (answer.Length <= 0)
{
answer = null;
}
}
}
else if (e.KeyData == Keys.Space && secret == true)
{
e.SuppressKeyPress = true;
answer += " ";
textBox1.Text += normal[i];
textBox1.Select(textBox1.Text.Length, 0);
i++;
}
else if (Control.ModifierKeys == Keys.Shift && secret == true)
{
e.SuppressKeyPress = true;
textBox1.Select(textBox1.Text.Length, 0);
}
}
将其移至KeyUp将阻止内存中的字符串在保留退格时被连续删除，正如您在Don的回答中的评论中所怀疑的那样。