blocks|key|568188|text|File.ReadAllText怎么样？|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|568189|string+contents+=+File.ReadAllText(@"C:\temp\test.txt");|code-block|syntax|javascript|568190|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.microsoft.com/en-us/dotnet/api/system.io.file.readalltext^0|0|G|0|G|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@$9|V|A|W|1|X]]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

How about <a href="https://docs.microsoft.com/en-us/dotnet/api/system.io.file.readalltext" rel="noreferrer"><code>File.ReadAllText</code></a>:

<pre><code>string contents = File.ReadAllText(@"C:\temp\test.txt");
</code></pre>

blocks|key|784291|text|System.IO.StreamReader+myFile+=
+++new+System.IO.StreamReader("c:\\test.txt");
string+myString+=+myFile.ReadToEnd();|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|784292|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>System.IO.StreamReader myFile =
 new System.IO.StreamReader("c:\\test.txt");
string myString = myFile.ReadToEnd();
</code></pre>

blocks|key|784306|text|string+contents+=+System.IO.File.ReadAllText(path)|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|784307|这是MSDN+documentation|unstyled|offset|length|784308|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/ms143368.aspx^0|0|2|I|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|R|8|@]|9|@$G|S|H|T|1|U]]|A|$]]|$1|I|3|-4|5|F|7|V|8|@]|9|@]|A|$]]]|J|$K|$5|L|M|N|A|$O|P]]]]

<pre><code>string contents = System.IO.File.ReadAllText(path)
</code></pre>

Here's the <a href="http://msdn.microsoft.com/en-us/library/ms143368.aspx" rel="noreferrer">MSDN documentation</a>

blocks|key|568244|text|好的，最快的方式意味着使用最少的C#代码，可能是这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|568245|string+readText+=+System.IO.File.ReadAllText(path);|code-block|syntax|javascript|568246|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|$]]

well the quickest way meaning with the least possible C# code is probably this one:

<pre><code>string readText = System.IO.File.ReadAllText(path);
</code></pre>

blocks|key|784479|text|string+content+=+System.IO.File.ReadAllText(+@"C:\file.txt"+);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|784480|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>string content = System.IO.File.ReadAllText( @"C:\file.txt" );
</code></pre>

blocks|key|784518|text|您还可以将文本文件中的文本读入字符串，如下所示|type|unstyled|depth|inlineStyleRanges|entityRanges|data|784519|string+str+=+"";
StreamReader+sr+=+new+StreamReader(Application.StartupPath+%2B+"\\Sample.txt");
while(sr.Peek()+!=+-1)
{
++str+=+str+%2B+sr.ReadLine();
}|code-block|syntax|javascript|784520|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 can read a text from a text file in to string as follows also

<pre><code>string str = "";
StreamReader sr = new StreamReader(Application.StartupPath + "\\Sample.txt");
while(sr.Peek() != -1)
{
 str = str + sr.ReadLine();
}
</code></pre>

blocks|key|568534|text|@Cris对不起，.This是引用MSDN+Microsoft|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|568535|方法论|568536|在本实验中，将对两个班级进行比较。StreamReader和FileStream类将被指示从应用程序目录中读取10K和200K的两个文件。|568537|StreamReader+(VB.NET)

sr+=+New+StreamReader(strFileName)
Do
++line+=+sr.ReadLine()
Loop+Until+line+Is+Nothing
sr.Close()

FileStream+(VB.NET)

Dim+fs+As+FileStream
Dim+temp+As+UTF8Encoding+=+New+UTF8Encoding(True)
Dim+b(1024)+As+Byte
fs+=+File.OpenRead(strFileName)
Do+While+fs.Read(b,+0,+b.Length)+>+0
++++temp.GetString(b,+0,+b.Length)
Loop
fs.Close()|code-block|syntax|javascript|568538|结果|568539|​|568540|📷|atomic|568541|568542|在这个测试中，FileStream显然更快。StreamReader读取这个小文件要多花50%25的时间。对于大文件，需要额外花费27%25的时间。|568543|StreamReader专门寻找换行符，而FileStream则不是。这将解释一些额外的时间。|568544|建议|568545|根据应用程序需要对一段数据做什么，可能会有额外的解析，这将需要额外的处理时间。考虑这样一个场景，其中一个文件包含多列数据，并且这些行是以CR/LF分隔的。StreamReader将遍历查找CR/LF的文本行，然后应用程序将执行额外的解析以查找特定位置的数据。(你认为字符串。SubString是免费的吗？)|568546|另一方面，FileStream以块的形式读取数据，主动开发人员可以编写更多的逻辑来使用流，以使其受益。如果需要的数据在文件中的特定位置，这肯定是一种方法，因为它可以降低内存使用量。|568547|FileStream是更好的速度机制，但需要更多的逻辑。|568548|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/5d7d63265eb045f8f4ed8f7be366b9c1.jpeg|imageAlt^0|H|E|0|0|H|C|U|A|0|0|0|0|0|1|0|0|0|7|A|M|C|0|0|C|L|A|0|0|1W|5|25|C|2M|5|0|5|A|0|0|A|0^^$0|@$1|2|3|4|5|6|7|1H|8|@$9|1I|A|1J|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|1K|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|1L|8|@$9|1M|A|1N|B|C]|$9|1O|A|1P|B|C]]|D|@]|E|$]]|$1|J|3|K|5|L|7|1Q|8|@]|D|@]|E|$M|N]]|$1|O|3|P|5|6|7|1R|8|@]|D|@]|E|$]]|$1|Q|3|R|5|6|7|1S|8|@]|D|@]|E|$]]|$1|S|3|T|5|U|7|1T|8|@]|D|@$9|1U|A|1V|1|1W]]|E|$]]|$1|V|3|R|5|6|7|1X|8|@]|D|@]|E|$]]|$1|W|3|X|5|6|7|1Y|8|@$9|1Z|A|20|B|C]|$9|21|A|22|B|C]]|D|@]|E|$]]|$1|Y|3|Z|5|6|7|23|8|@$9|24|A|25|B|C]|$9|26|A|27|B|C]]|D|@]|E|$]]|$1|10|3|11|5|6|7|28|8|@]|D|@]|E|$]]|$1|12|3|13|5|6|7|29|8|@$9|2A|A|2B|B|C]|$9|2C|A|2D|B|C]|$9|2E|A|2F|B|C]]|D|@]|E|$]]|$1|14|3|15|5|6|7|2G|8|@$9|2H|A|2I|B|C]]|D|@]|E|$]]|$1|16|3|17|5|6|7|2J|8|@$9|2K|A|2L|B|C]]|D|@]|E|$]]|$1|18|3|-4|5|6|7|2M|8|@]|D|@]|E|$]]]|19|$1A|$5|1B|1C|1D|E|$1E|1F|1G|-4]]]]

@Cris sorry .This is quote <code>MSDN Microsoft</code> 

Methodology

In this experiment, two classes will be compared. The <code>StreamReader</code> and the <code>FileStream</code> class will be directed to read two files of 10K and 200K in their entirety from the application directory.

<pre><code>StreamReader (VB.NET)

sr = New StreamReader(strFileName)
Do
 line = sr.ReadLine()
Loop Until line Is Nothing
sr.Close()

FileStream (VB.NET)

Dim fs As FileStream
Dim temp As UTF8Encoding = New UTF8Encoding(True)
Dim b(1024) As Byte
fs = File.OpenRead(strFileName)
Do While fs.Read(b, 0, b.Length) &gt; 0
 temp.GetString(b, 0, b.Length)
Loop
fs.Close()
</code></pre>

Result

<img src="https://i.stack.imgur.com/wK6TW.jpg" alt="enter image description here">

<code>FileStream</code> is obviously faster in this test. It takes an additional 50% more time for <code>StreamReader</code> to read the small file. For the large file, it took an additional 27% of the time.

<code>StreamReader</code> is specifically looking for line breaks while <code>FileStream</code> does not. This will account for some of the extra time.

Recommendations

Depending on what the application needs to do with a section of data, there may be additional parsing that will require additional processing time. Consider a scenario where a file has columns of data and the rows are <code>CR/LF</code> delimited. The <code>StreamReader</code> would work down the line of text looking for the <code>CR/LF</code>, and then the application would do additional parsing looking for a specific location of data. (Did you think String. SubString comes without a price?)

On the other hand, the <code>FileStream</code> reads the data in chunks and a proactive developer could write a little more logic to use the stream to his benefit. If the needed data is in specific positions in the file, this is certainly the way to go as it keeps the memory usage down.

<code>FileStream</code> is the better mechanism for speed but will take more logic.

blocks|key|784746|text|string+text+=+File.ReadAllText("Path");将所有文本放在一个字符串变量中。如果您需要单独使用每一行，您可以使用以下命令：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|784747|string[]+lines+=+File.ReadAllLines("Path");|code-block|syntax|javascript|784748|entityMap^0|0|13|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|$]]

<code>string text = File.ReadAllText("Path");</code> you have all text in one string variable. If you need each line individually you can use this:

<pre><code>string[] lines = File.ReadAllLines("Path");
</code></pre>

blocks|key|568724|text|我对2MbCSV的ReadAllText和StreamBuffer进行了比较，差异似乎很小，但ReadAllText似乎在完成功能所需的时间上占据了上风。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|568725|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|$]]

I made a comparison between a ReadAllText and StreamBuffer for a 2Mb csv and it seemed that the difference was quite small but ReadAllText seemed to take the upper hand from the times taken to complete functions.

blocks|key|785081|text|如果你想从应用程序的Bin文件夹中选择文件，那么你可以尝试如下操作，不要忘了做异常处理。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|785082|string+content+=+File.ReadAllText(Path.Combine(System.IO.Directory.GetCurrentDirectory(),+@"FilesFolder\Sample.txt"));|code-block|syntax|javascript|785083|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|$]]

if you want to pick file from Bin folder of the application then you can try following and don't forget to do exception handling.

<pre><code>string content = File.ReadAllText(Path.Combine(System.IO.Directory.GetCurrentDirectory(), @"FilesFolder\Sample.txt"));
</code></pre>

blocks|key|785230|text|对于那些觉得这个东西有趣而有趣的新手来说，在大多数情况下，将整个文件读入字符串的最快方法(according+to+these+benchmarks)是这样的：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|785231|using+(StreamReader+sr+=+File.OpenText(fileName))
{
++++++++string+s+=+sr.ReadToEnd();
}
//you+then+have+to+process+the+string|code-block|syntax|javascript|785232|但是，读取文本文件的总体绝对最快速度似乎如下所示：|785233|using+(StreamReader+sr+=+File.OpenText(fileName))
{
++++++++string+s+=+String.Empty;
++++++++while+((s+=+sr.ReadLine())+!=+null)
++++++++{
+++++++++++++++//do+what+you+have+to+here
++++++++}
}|785234|Put+up+against+several+other+techniques，它在大多数情况下都赢了，包括对BufferedReader。|785235|entityMap|0|LINK|mutability|MUTABLE|url|http://cc.davelozinski.com/c-sharp/fastest-way-to-read-text-files|1^0|19|T|0|0|0|0|0|0|13|1|0^^$0|@$1|2|3|4|5|6|7|X|8|@]|9|@$A|Y|B|Z|1|10]]|C|$]]|$1|D|3|E|5|F|7|11|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|12|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|13|8|@]|9|@]|C|$G|H]]|$1|M|3|N|5|6|7|14|8|@]|9|@$A|15|B|16|1|17]]|C|$]]|$1|O|3|-4|5|6|7|18|8|@]|9|@]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]|W|$5|R|S|T|C|$U|V]]]]

For the noobs out there who find this stuff fun and interesting, the fastest way to read an entire file into a string in most cases (<a href="http://cc.davelozinski.com/c-sharp/fastest-way-to-read-text-files" rel="noreferrer" title="according to these benchmarks">according to these benchmarks</a>) is by the following:

<pre><code>using (StreamReader sr = File.OpenText(fileName))
{
 string s = sr.ReadToEnd();
}
//you then have to process the string
</code></pre>

However, the absolute fastest to read a text file overall appears to be the following:

<pre><code>using (StreamReader sr = File.OpenText(fileName))
{
 string s = String.Empty;
 while ((s = sr.ReadLine()) != null)
 {
 //do what you have to here
 }
}
</code></pre>

<a href="http://cc.davelozinski.com/c-sharp/fastest-way-to-read-text-files" rel="noreferrer" title="Put up against several other techniques">Put up against several other techniques</a>, it won out most of the time, including against the BufferedReader.

blocks|key|569013|text|您可以使用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|569014|+public+static+void+ReadFileToEnd()
{
++++try
++++{
++++//provide+to+reader+your+complete+text+file
++++++++using+(StreamReader+sr+=+new+StreamReader("TestFile.txt"))
++++++++{
++++++++++++String+line+=+sr.ReadToEnd();
++++++++++++Console.WriteLine(line);
++++++++}
++++}
++++catch+(Exception+e)
++++{
++++++++Console.WriteLine("The+file+could+not+be+read:");
++++++++Console.WriteLine(e.Message);
++++}
}|code-block|syntax|javascript|569015|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 can use :

<pre><code> public static void ReadFileToEnd()
{
 try
 {
 //provide to reader your complete text file
 using (StreamReader sr = new StreamReader("TestFile.txt"))
 {
 String line = sr.ReadToEnd();
 Console.WriteLine(line);
 }
 }
 catch (Exception e)
 {
 Console.WriteLine("The file could not be read:");
 Console.WriteLine(e.Message);
 }
}
</code></pre>

blocks|key|785319|text|您可以像这样使用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|785320|public+static+string+ReadFileAndFetchStringInSingleLine(string+file)
++++{
++++++++StringBuilder+sb;
++++++++try
++++++++{
++++++++++++sb+=+new+StringBuilder();
++++++++++++using+(FileStream+fs+=+File.Open(file,+FileMode.Open))
++++++++++++{
++++++++++++++++using+(BufferedStream+bs+=+new+BufferedStream(fs))
++++++++++++++++{
++++++++++++++++++++using+(StreamReader+sr+=+new+StreamReader(bs))
++++++++++++++++++++{
++++++++++++++++++++++++string+str;
++++++++++++++++++++++++while+((str+=+sr.ReadLine())+!=+null)
++++++++++++++++++++++++{
++++++++++++++++++++++++++++sb.Append(str);
++++++++++++++++++++++++}
++++++++++++++++++++}
++++++++++++++++}
++++++++++++}
++++++++++++return+sb.ToString();
++++++++}
++++++++catch+(Exception+ex)
++++++++{
++++++++++++return+"";
++++++++}
++++}|code-block|syntax|javascript|785321|希望这能对你有所帮助。|785322|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You can use like this

<pre><code>public static string ReadFileAndFetchStringInSingleLine(string file)
 {
 StringBuilder sb;
 try
 {
 sb = new StringBuilder();
 using (FileStream fs = File.Open(file, FileMode.Open))
 {
 using (BufferedStream bs = new BufferedStream(fs))
 {
 using (StreamReader sr = new StreamReader(bs))
 {
 string str;
 while ((str = sr.ReadLine()) != null)
 {
 sb.Append(str);
 }
 }
 }
 }
 return sb.ToString();
 }
 catch (Exception ex)
 {
 return "";
 }
 }
</code></pre>

Hope this will help you.

What is the quickest way to read a text file into a string variable?

I understand it can be done in several ways, such as read individual bytes and then convert those to string. I was looking for a method with minimal coding.

How to read an entire file to a string using C#?

将文本文件读入字符串变量的最快方法是什么？我知道这可以通过几种方式来完成，比如读取单个字节，然后将其转换为字符串。我在寻找一种编码最少的方法。

问如何使用C#将整个文件读取为字符串？
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