blocks|key|910141|text|只有MyString[0]。这使用String.Chars索引器。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|910142|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/system.string.chars.aspx^0|2|B|H|C|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]]|D|@$9|Q|A|R|1|S]]|E|$]]|$1|F|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

Just <code>MyString[0]</code>. This uses the <a href="http://msdn.microsoft.com/en-us/library/system.string.chars.aspx" rel="noreferrer">String.Chars</a> indexer.

blocks|key|1125182|text|Mystring[0]应该足够了|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1125183|entityMap^0|0|B|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

<code>Mystring[0]</code> should be enough

blocks|key|1125332|text|尝尝这个,|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1125333|string+s1="good";+++string+s=s1.Substring(0,1);|offset|length|style|CODE|1125334|entityMap^0|0|0|1B|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

Try this,

<code>string s1="good"; 
 string s=s1.Substring(0,1);</code>

blocks|key|910302|text|您可以使用LINQ|type|unstyled|depth|inlineStyleRanges|entityRanges|data|910303|char+c+=+mystring.FirstOrDefault()|code-block|syntax|javascript|910304|如果字符串为空，则等于'\0'。|offset|length|style|CODE|910305|entityMap^0|0|0|B|4|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

You can use LINQ

<pre><code>char c = mystring.FirstOrDefault()
</code></pre>

It will be equal to <code>'\0'</code> if the string is empty.

blocks|key|1125277|text|MyString[0]和MyString.ToCharArray()[0]的不同之处在于前者将字符串视为只读数组，而ToCharArray()则创建一个新数组。前者对于几乎任何可以工作的地方都会更快(同时也更容易)，但是如果你有一个需要接受数组的方法，或者如果你想改变数组，那么ToCharArray可能是必要的。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1125278|如果不知道字符串是否是非空和非空的，您可以这样做：|1125279|string.IsNullOrEmpty(MyString)+?+(char?)null+:+MyString[0]|code-block|syntax|javascript|1125280|它根据需要返回null或字符串中的第一个字符的char?。|1125281|entityMap^0|0|B|C|P|1M|D|3V|B|0|0|0|N|5|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]|$9|T|A|U|B|C]|$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Z|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|10|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|11|8|@$9|12|A|13|B|C]]|D|@]|E|$]]|$1|O|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|P|$]]

The difference between <code>MyString[0]</code> and <code>MyString.ToCharArray()[0]</code> is that the former treats the string as a read-only array, while <code>ToCharArray()</code> creates a new array. The former will be quicker (along with easier) for almost anything where it will work, but <code>ToCharArray</code> can be necessary if you have a method that needs to accept an array, or if you want to change the array.

If the string isn't known to be non-null and non-empty you could do:

<pre><code>string.IsNullOrEmpty(MyString) ? (char?)null : MyString[0]
</code></pre>

which returns a <code>char?</code> of either null or the first character in the string, as appropriate.

blocks|key|1125204|text|或者你可以这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1125205|MyString[0];|code-block|syntax|javascript|1125206|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|$]]

Or you can do this:

<pre><code>MyString[0];
</code></pre>

blocks|key|1125328|text|只是另一种方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1125329|string+mystr+=+"hello";
MessageBox.show(mystr.Substring(0,+1));|code-block|syntax|javascript|1125330|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|$]]

Just another approach:

<pre><code>string mystr = "hello";
MessageBox.show(mystr.Substring(0, 1));
</code></pre>

blocks|key|1125242|text|我想你是在找这个MyString.ToCharArray()[0]|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1125243|:)|1125244|但是你也可以使用MyString[0]。|1125245|entityMap^0|8|P|0|0|8|B|0^^$0|@$1|2|3|4|5|6|7|L|8|@$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|O|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@]|E|$]]|$1|J|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|K|$]]

I think you are looking for this <code>MyString.ToCharArray()[0]</code>

:)

But you can use <code>MyString[0]</code> too.

blocks|key|1125497|text|在C#+8中，您可以使用范围。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1125498|myString[0..Math.Min(myString.Length,+1)]|code-block|syntax|javascript|1125499|在myString后面添加一个?来处理null字符串。|offset|length|style|CODE|1125500|entityMap^0|0|0|1|8|F|1|J|4|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]|$I|V|J|W|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|N|$]]

In C# 8 you can use ranges.

<pre><code>myString[0..Math.Min(myString.Length, 1)]
</code></pre>

Add a <code>?</code> after <code>myString</code> to handle <code>null</code> strings.

blocks|key|1125560|text|从C#+8.0%2B开始，我们可以使用范围索引器语法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1125561|以下代码：|1125562|var+name+=+"Dotnet".Substring(0,+1)|code-block|syntax|javascript|1125563|可以使用范围语法来编写：|1125564|var+name+=+"Dotnet"[..1]|1125565|Try+it+out+in+Dotnet+fiddle|offset|length|1125566|See+official+docs+for+more+examples|1125567|entityMap|0|LINK|mutability|MUTABLE|url|https://dotnetfiddle.net/K2FyV1|1|https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-8#indices-and-ranges^0|0|0|0|0|0|0|R|0|0|0|Z|1|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|13|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|14|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|15|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|16|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|17|8|@]|9|@$O|18|P|19|1|1A]]|A|$]]|$1|Q|3|R|5|6|7|1B|8|@]|9|@$O|1C|P|1D|1|1E]]|A|$]]|$1|S|3|-4|5|6|7|1F|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z]]|10|$5|V|W|X|A|$Y|11]]]]

Starting with C# 8.0+ we can use the range indexer syntax.
The following code:
<pre class="lang-cs prettyprint-override"><code>var name = &quot;Dotnet&quot;.Substring(0, 1)
</code></pre>
can be written using range syntax:
<pre><code>var name = &quot;Dotnet&quot;[..1]
</code></pre>
<a href="https://dotnetfiddle.net/K2FyV1" rel="nofollow noreferrer">Try it out in Dotnet fiddle</a>
<a href="https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-8#indices-and-ranges" rel="nofollow noreferrer">See official docs for more examples</a>

blocks|key|1125408|text|MyString.Remove(1，2)；也适用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1125409|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

MyString.Remove(1, 2); also works

blocks|key|1125467|text|你的问题的答案是否定的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1125468|正确的是字符的MyStringposition。对于MyString，0是任何字符串的第一个字符。|1125469|字符值用‘(单引号)表示，就像这个x字符值写成'x’一样。|1125470|字符串值用“(双引号)表示，就像这个x字符串值写成"x”一样。|1125471|所以Substring()方法也不返回字符，Substring()方法返回字符串！|1125472|字符串是一个字符数组，最后一个字符必须是'\0‘(空)字符。这就是字符数组和字符串(即最后一个字符作为“字符串结束标记”'\0‘null的字符数组)之间的区别。|1125473|还要注意'x‘不等于’x‘。因为"x“实际上是'x'%2B'\0‘。|1125474|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|S|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|T|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|U|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|V|8|@]|9|@]|A|$]]|$1|N|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|O|$]]

Answer to your question is NO.

Correct is MyString[position of character]. For your case MyString[0], 0 is the FIRST character of any string.

A character value is designated with ' (single quote), like this x character value is written as 'x'.

A string value is designated with " ( double quote), like this x string value is written as "x".

So Substring() method is also does not return a character, Substring() method returns a string!!!

A string is an array of characters, and last character must be '\0' (null) character. Thats the difference between character array and string ( which is an array of characters with last character as "end of string marker" '\0' null.

And also notice that 'x' IS NOT EQUAL to "x".
Because "x" is actually 'x'+'\0'.

blocks|key|910536|text|也许这会有帮助。我使用txtModel_Leave事件然后创建方法来检测主文本框中的第一个字符。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|910537|private+void+txtMain_Leave(object+sender,+EventArgs+e)
{
++++detectFirstChar();
}

private+void+detectFirstChar()+
{
++++string+mystr+=+txtModel.Text;

++++if+(String.IsNullOrEmpty(txtModel.Text))
++++{
++++++++txtAwalan.Text+=+"";
++++}
++++else+if+(mystr.Substring(0,+1)+==+"F")
++++{
++++++++txtKategori.Text+=+"Finishing";+++++++++++++++
++++}
++++else+if((mystr.Substring(0,+1)+==+"H"))
++++{
++++++++txtKategori.Text+=+"Half";
++++}
++++else
++++{
++++++++txtKategori.Text+=+"NONE";
++++}
}|code-block|syntax|javascript|910538|entityMap^0|B|E|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Maybe this will help. I'm using <code>txtModel_Leave</code> event then create method to detect the first char in main textbox.
<pre><code>private void txtMain_Leave(object sender, EventArgs e)
{
 detectFirstChar();
}

private void detectFirstChar() 
{
 string mystr = txtModel.Text;

 if (String.IsNullOrEmpty(txtModel.Text))
 {
 txtAwalan.Text = &quot;&quot;;
 }
 else if (mystr.Substring(0, 1) == &quot;F&quot;)
 {
 txtKategori.Text = &quot;Finishing&quot;; 
 }
 else if((mystr.Substring(0, 1) == &quot;H&quot;))
 {
 txtKategori.Text = &quot;Half&quot;;
 }
 else
 {
 txtKategori.Text = &quot;NONE&quot;;
 }
}
</code></pre>

blocks|key|910389|text|从字符串中获取字符可能取决于编码(字符串默认为UTF-16)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|910390|https://stackoverflow.com/a/32141891|offset|length|910391|string+str+=+new+String(new+char[]+{+'\uD800',+'\uDC00',+'z'+});
string+first+=+str.Substring(0,+char.IsHighSurrogate(str[0])+?+2+:+1);|code-block|syntax|javascript|910392|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|10|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@$D|T|E|U|1|V]]|A|$]]|$1|F|3|G|5|H|7|W|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|C]]]]

getting a char from a string may depend on the enconding (string default is UTF-16) 

<a href="https://stackoverflow.com/a/32141891">https://stackoverflow.com/a/32141891</a>

<pre><code>string str = new String(new char[] { '\uD800', '\uDC00', 'z' });
string first = str.Substring(0, char.IsHighSurrogate(str[0]) ? 2 : 1);
</code></pre>

Can the first <code>char</code> of a string be retrieved by doing the following?

<pre><code>MyString.ToCharArray[0]
</code></pre>

C#: how to get first char of a string?

可以通过执行以下操作来检索字符串的第一个char吗？MyString.ToCharArray[0]

问C#：如何获取字符串的第一个字符？
EN

回答 14

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问C#：如何获取字符串的第一个字符？
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