[英]C# - How to override actions for “Up arrow” and “Down arrow” for a textbox?
[英]C# TextBox Override Arrow Key Select Function
基本上,从这个问题继续,当用户按下shift
+向左或向右时,我需要它来选择整个字符组。
我拥有的当前代码(在PreviewKeyDown事件下):
string s;
int caretLocation = textBox1.SelectionStart;
string txt = textBox1.Text;
if (e.Shift)
{
switch (e.KeyCode)
{
#region Right
case Keys.Right:
{
s = txt.Substring(caretLocation);
foreach (string combo in charCombinations)
{
if (s.StartsWith(combo))
{
textBox1.SelectionLength = combo.Length - 1;
break;
}
}
break;
}
#endregion
#region Left
case Keys.Left:
{
s = txt.Substring(0, caretLocation);
foreach (string combo in charCombinations)
{
if (s.EndsWith(combo))
{
textBox1.SelectionStart = caretLocation - combo.Length + 1;
textBox1.SelectionLength = combo.Length + 1
break;
}
}
break;
}
#endregion
}
}
第一个问题在于右键,如果连续出现两个这样的字符组,则插入符号不会从下面显示的位置进一步向右移动:
第二个问题与左键有关,其中左键选择只是不能选择整个字符:
对于这种情况,应选择整个单词sin(
。
提前致谢!
charCombinations
已定义为:
private static readonly string[] charCombinations = new string[] { "asinh(", "acosh", "atanh(",
"sinh(", "cosh(", "tanh(", "asin(", "acos(", "atan(", "sin(", "cos(", "tan(",
"log(", "ln(", "PI", "e", "Phi"};
您必须将下一个文本长度添加到上一个长度。
我已将此模型固定为您的代码:
case Keys.Right:
{
s = txt.Substring(caretLocation);
foreach (string combo in charCombinations)
{
if (s.StartsWith(combo))
{
textBox1.SelectionLength += combo.Length - 1;
break;
}
}
break;
}
重要的行是: textBox1.SelectionLength += combo.Length - 1;
因为我用+=
代替=
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