使用streamwriter附加文本文件

问题描述

| 我有这段代码，我将按顺序运行以下代码。 我将始终在开始时创建一个新的文本文件。那么对于代码的第二部分和第三部分，我只需要附加文本文件“ checksnapshot \”，我该如何使用Streamwriter做到这一点？

//1
using (StreamReader sr = new StreamReader(\"C:\\\\Work\\\\labtoolssnapshot.txt\")) ;
{
    string contents = sr.ReadToEnd();
    using (StreamWriter sw = new StreamWriter(\"C:\\\\Work\\\\checksnapshot.properties\"))
    {
        if (contents.Contains(args[0]))
        {
            sw.WriteLine(\"SASE= 1\");
        }
        else
        {
            sw.WriteLine(\"SASE= 0\");
        }
    }
}

//2
using (StreamReader sr = new StreamReader(\"C:\\\\Work\\\\analyzercommonsnapshot.txt\")) ;
{
    string contents = sr.ReadToEnd();
    using (StreamWriter sw = new StreamWriter(\"C:\\\\Work\\\\checksnapshot.properties\"))
    {
        if (contents.Contains(args[0]))
        {
            sw.WriteLine(\"Analyzer= 1\");
        }
        else
        {
            sw.WriteLine(\"Analyzer= 0\");
        }
    }
}

//3
using (StreamReader sr = new StreamReader(\"C:\\\\Work\\\\mobilesnapshot.txt\")) ;
{
    string contents = sr.ReadToEnd();
    using (StreamWriter sw = new StreamWriter(\"C:\\\\Work\\\\checksnapshot.properties\"))
    {
        if (contents.Contains(args[0]))
        {
            sw.WriteLine(\"mobile= 1\");
        }
        else
        {
            sw.WriteLine(\"mobile= 0\");
        }
    }
}

    

解决方法

        那怎么办

new StreamWriter(\"C:\\\\Work\\\\checksnapshot.properties\",true)

如果文件存在，则true表示追加。     ,        通过使用

StreamWriter

的适当构造函数：

new StreamWriter(someFile,true)

将打开someFile并追加。     ,        我不是为什么您的代码不起作用，而是为什么您不使用内置方法：

string contents = File.ReadAllText(\"C:\\\\Work\\\\labtoolssnapshot.txt\");
string contents2 = File.ReadAllText(\"C:\\\\Work\\\\analyzercommonsnapshot.txt\");
string contents3 = File.ReadAllText(\"C:\\\\Work\\\\mobilesnapshot.txt\");
string outFile = \"C:\\\\Work\\\\checksnapshot.properties\";
//1 
if (contents.Contains(args[0]))
{
    File.WriteAllText(outFile,\"SASE=1\");
}
else
{
    File.WriteAllText(outFile,\"SASE=0\");
}
//2 
if (contents2.Contains(args[0]))
{
    File.AppendAllText(outFile,\"Analyzer= 1\");
}
else
{
    File.AppendAllText(outFile,\"Analyzer= 0\");
}

//3
if (contents3.Contains(args[0]))
{
    File.AppendAllText(outFile,\"mobile= 1\");
}
else
{
    File.AppendAllText(outFile,\"mobile= 0\");
}

或者，在更懒惰的代码中：

var contents = File.ReadAllText(\"C:\\\\Work\\\\labtoolssnapshot.txt\");
var contents2 = File.ReadAllText(\"C:\\\\Work\\\\analyzercommonsnapshot.txt\");
var contents3 = File.ReadAllText(\"C:\\\\Work\\\\mobilesnapshot.txt\");
var outFile = \"C:\\\\Work\\\\checksnapshot.properties\";

File.WriteAllText(outfile,string.Format(
@\"SASE= {0}
Analyzer= {1}
mobile= {2}
\",contents.Contains(args[0]) ? \"1\" : \"0\",contents2.Contains(args[0]) ? \"1\" : \"0\",contents3.Contains(args[0]) ? \"1\" : \"0\"
    ));

    ,        使用

FileStream

代替

StreamWriter

：

using (FileStream fs = new FileStream(\"C:\\\\Work\\\\checksnapshot.properties\",FileMode.OpenOrCreate,FileAccess.Append))
{
    StreamWriter writer = new StreamWriter(fs);
    writer.Write(whatever);
}

注意：我只在.NET 4中使用过