如何从文本框中删除项目c＃

问题描述：

我正在研究winapp。

这是一个机器人。

我想要添加和删除控制机器人的主人。

I'm working on a winapp.

It's a bot.

I want to add and delete masters who controls the bot.

//master add n remove
if (msg.Body != null && msg.Body.ToLower().StartsWith("addcon/"))
{                               
    textBox4.Text = textBox4.Text + msg.Body.ToLower().Replace("addcon/", "#");
}

if (msg.Body != null && msg.Body.ToLower().StartsWith("delcon/"))
{
                               
    string str = msg.Body.ToLower().Replace("delcon/", "");
    textBox4.Text.Replace(str + "#", "");
}

在上面的代码中，addcon / xyz命令被赋予bot来添加xyz到它的控制器，在textbox4中添加xyz＃

和delcon / xyz用于从textbox4中删除xyz＃

textbox4收集所有可通过远程命令控制机器人的机器人大师。

delcon无法正常工作。

任何帮助？

In the above code addcon/xyz command is given to bot to add xyz to its controller that adds xyz# in textbox4

and delcon/xyz coomand is given to delete xyz# from textbox4

textbox4 collects all ids of bot masters who can control the bot by remote commands.

The delcon is not working properly.

Any help?

答

只需添加到Mehdi所说的：替换不能就地工作 - 这意味着它不会修改现有的字符串，而是返回一个新的字符串，其中应用了更改（如果有）， ，这同样适用于所有其他字符串方法 。

这是因为字符串是不可变的：一旦创建它们就无法更改。如果它们是可变的那么：

Just to add to what Mehdi said: Replace does not work in-place - which means it does not modify the existing string but returns a new string with the changes (if any) applied, and the same applies to every other string method.

This is because strings are immutable: they cannot be changed once created. If they were mutable then this:

string s1 = "Hello there!";
string s2 = s1;
s2.Replace("there", "World");

会导致更改发生在 s1 和 s2 因为它们都引用相同的字符串实例。

相反，它返回一个新的字符串，所以这个：

Would cause the change to happen to both s1 and s2 since they both reference the same string instance.
Instead, it returns a new string, so this:

string s1 = "Hello there!";
string s2 = s1;
s2 = s2.Replace("there", "World");
Console.WriteLine(s1);
Console.WriteLine(s2);

会打印

Would print

Hello there!
Hello World!

哪个更有用。

替换（） 不就地操作并返回一个字符串，所以：

Replace() does not operate in-place and gives you back a string, so :

textbox4.Text = textBox4.Text.Replace(str + "#", "");

请参阅我对该问题的评论。很难想象用一根弦操作会需要任何特别的帮助，除非你特别混淆了某些东西。

然而，使用 TextBox 似乎很糟糕。如果您将 TextBox.Text 字符串的部分视为项目，请使用一些控件来代替项目：组合框，列表框，列表视图或更复杂的内容。 />

-SA

Please see my comment to the question. It's hard to imagine that the manipulation with one string would need any special help, unless you have a confusion with something in particular.

However, the whole idea of using TextBox seems to be bad. If you consider parts of the TextBox.Text string as "items", use some control with items instead: combo box, list box, list view or something more complex.

—SA

如何从文本框中删除项目c＃

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