blocks|key|5335243|text|我无法访问您的链接图像，所以我不确定message包含什么内容，但是|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|5335244|String+zoneNumber+=+message.Substring(5,+message.Length);|code-block|syntax|javascript|5335245|应该抛出异常，因为它会使字符串的长度溢出5个字符。|5335246|使用|5335247|String+zoneNumber+=+message.Substring(5);|5335248|而不是。|5335249|entityMap^0|I|7|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Y|8|@]|D|@]|E|$]]|$1|M|3|N|5|6|7|Z|8|@]|D|@]|E|$]]|$1|O|3|P|5|H|7|10|8|@]|D|@]|E|$I|J]]|$1|Q|3|R|5|6|7|11|8|@]|D|@]|E|$]]|$1|S|3|-4|5|6|7|12|8|@]|D|@]|E|$]]]|T|$]]

I can't access your linked image, so I don't know for certain what <code>message</code> contains, but

<pre><code>String zoneNumber = message.Substring(5, message.Length);
</code></pre>

should throw an exception as it would overflow the length of the string by 5 characters.

Use

<pre><code>String zoneNumber = message.Substring(5);
</code></pre>

instead.

blocks|key|1983657|text|改一下怎么样？|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1983658|String+zoneNumber+=+message.Substring(5,+message.Length);|code-block|syntax|javascript|1983659|至|1983660|String+zoneNumber+=+message.Substring(5);|1983661|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

How about changing

<pre><code>String zoneNumber = message.Substring(5, message.Length);
</code></pre>

to

<pre><code>String zoneNumber = message.Substring(5);
</code></pre>

blocks|key|754286|text|type|unstyled|depth|inlineStyleRanges|entityRanges|data|754287|我想要显示字符串的数字部分，但是当我尝试这样做时，什么也没有显示|blockquote|754288|754289|754290|这是因为，查看您的消息，它包含前导空格，而您正在尝试执行StartsWith("<BID>")|offset|length|style|CODE|754291|首先使用TrimStart，然后尝试使用StartsWith，或者直接使用Contains。|754292|StartsWith|754293|if+(message.TrimStart().StartsWith("<BID>"))
{
++++MessageBox.Show("Bid+received+for+zone+"+%2B+zoneNumber);
}|code-block|syntax|javascript|754294|entityMap^0|0|0|0|0|S|J|0|4|9|K|A|11|8|0|0|A|0|0^^$0|@$1|2|3|-4|4|5|6|W|7|@]|8|@]|9|$]]|$1|A|3|B|4|C|6|X|7|@]|8|@]|9|$]]|$1|D|3|-4|4|5|6|Y|7|@]|8|@]|9|$]]|$1|E|3|-4|4|5|6|Z|7|@]|8|@]|9|$]]|$1|F|3|G|4|5|6|10|7|@$H|11|I|12|J|K]]|8|@]|9|$]]|$1|L|3|M|4|5|6|13|7|@$H|14|I|15|J|K]|$H|16|I|17|J|K]|$H|18|I|19|J|K]]|8|@]|9|$]]|$1|N|3|O|4|5|6|1A|7|@$H|1B|I|1C|J|K]]|8|@]|9|$]]|$1|P|3|Q|4|R|6|1D|7|@]|8|@]|9|$S|T]]|$1|U|3|-4|4|5|6|1E|7|@]|8|@]|9|$]]]|V|$]]

<blockquote>
 I want to display the number part of the string, however when I try doing this nothing is displayed
</blockquote>

That's because, looking at your message, it has leading whitespace and you are trying to do <code>StartsWith("&lt;BID&gt;")</code>

First, <code>TrimStart</code>, then try <code>StartsWith</code>, or just do <code>Contains</code>.

<code>StartsWith</code>:

<pre><code>if (message.TrimStart().StartsWith("&lt;BID&gt;"))
{
 MessageBox.Show("Bid received for zone " + zoneNumber);
}
</code></pre>

blocks|key|5817544|text|可以使用rplace而不是SubString|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5817545|if+(message.StartsWith("<BID>"))
{
++++MessageBox.Show("Bid+received+for+zone+"+%2B+message.Replace("<BID>",""));
}|code-block|syntax|javascript|5817546|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You could use rplace instead of SubString

<pre><code>if (message.StartsWith("&lt;BID&gt;"))
{
 MessageBox.Show("Bid received for zone " + message.Replace("&lt;BID&gt;",""));
}
</code></pre>

blocks|key|1983861|text|那么问题是if+(message.StartsWith("<BID>"))没有返回true吗？|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1983862|这有帮助吗？|1983863|public+void+parseMessage(string+theMessage)
{
+++++++String+message+=+theMessage.Replace("\r",+String.Empty).Replace("\n",+String.Empty).Replace("\r\n",+String.Empty);
+++++++MessageBox.Show("Received+%7C"+%2B+message+%2B+"%7C");
+++++++String+zoneNumber+=+message.Substring(5,+message.Length);
+++++++if+(message.TrimStart().StartsWith("<BID>"))
+++++++{
++++++++++MessageBox.Show("Bid+received+for+zone+"+%2B+zoneNumber);
+++++++}
}|code-block|syntax|javascript|1983864|entityMap^0|5|W|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|R|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|S|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

so the problem is that <code>if (message.StartsWith("&lt;BID&gt;"))</code> does not return true?

does this help?

<pre><code>public void parseMessage(string theMessage)
{
 String message = theMessage.Replace("\r", String.Empty).Replace("\n", String.Empty).Replace("\r\n", String.Empty);
 MessageBox.Show("Received |" + message + "|");
 String zoneNumber = message.Substring(5, message.Length);
 if (message.TrimStart().StartsWith("&lt;BID&gt;"))
 {
 MessageBox.Show("Bid received for zone " + zoneNumber);
 }
}
</code></pre>

blocks|key|5817731|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5817732|String+bidMarker+=+"<BID>";
int+startLoc+=+message.IndexOf(bid);
if+(startLoc+!=+-1)
{
++++String+zoneNumber+=+message.Substring(startLoc+%2B+bidMarker.Length).Trim();
++++MessageBox.Show("Bid+received+for+zone+"+%2B+zoneNumber);
}|code-block|syntax|javascript|5817733|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try this:

<pre><code>String bidMarker = "&lt;BID&gt;";
int startLoc = message.IndexOf(bid);
if (startLoc != -1)
{
 String zoneNumber = message.Substring(startLoc + bidMarker.Length).Trim();
 MessageBox.Show("Bid received for zone " + zoneNumber);
}
</code></pre>

I am trying to display part of a <code>string</code> using a <code>MessageBox</code>, for this I use the <code>String.SubString</code> method. However when I run the code the <code>MessageBox</code> is not displayed and no error is thrown. 

For troubleshooting purposes I display the entire string in a <code>MessageBox</code> before trying to display the <code>substring</code>.

This displays the following (<code>Received |&lt;BID&gt;22|</code>):

<img src="https://imgur.com/0cYe3kV.jpg" alt="">

I want to display the number part of the string, however when I try doing this nothing is displayed. Can anyone see what is going wrong please? Here is the code:

<pre><code>public void parseMessage(string theMessage)
{
 String message = theMessage.Replace("\n", String.Empty);

 MessageBox.Show("Received |" + message + "|");

 String zoneNumber = message.Substring(5, message.Length);

 if (message.StartsWith("&lt;BID&gt;"))
 {
 MessageBox.Show("Bid received for zone " + zoneNumber);
 }
}
</code></pre>

C# String.SubString With MessageBox Does Not Display Anything

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在尝试使用MessageBox显示string的一部分，为此我使用了String.SubString方法。但是，当我运行代码时，MessageBox不会显示，也不会抛出错误。出于故障排除的目的，我在尝试显示substring之前在MessageBox中显示了整个字符串。这将显示以下内容(Received |<BID...

问带有MessageBox的C# String.SubString不显示任何内容
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问带有MessageBox的C# String.SubString不显示任何内容EN