如何使用C＃将文本文件中的文本添加到字符串 [英] How to add text in a textfile to a string using C#

问题描述

我使用打开文件对话框选择了一个文件。



然后我需要将文件中的所有文本内容添加到字符串变量中。



怎么做。

I have selected a file using open file dialog.

Then I need to add all the text contents in the file to a string variable.

How to do so.

推荐答案

你可以这样做：

You could just do this:

string s = "my original content";
s += File.ReadAllText(path);

但效率非常低：

But that is pretty inefficient:

string s = "my original content";
string fileData = File.ReadAllText(path);
StringBuilder sb = new StringBuilder(s.Length + fileData.Length);
sb.Append(s);
sb.Append(fileData);
s = sb.ToString();

可能会更好，特别是如果你这么做，可以重复使用StringBuilder



我正在使用打开文件对话框在运行时选择5个文件。



如何创建五个字符串运行时将所有文本文件存储在适当的字符串中



试试这个：

Might be better, particularly if you are doing this a lot and can re-use the StringBuilder

"I am using open file dialog to select 5 files at runtime.

How to create five strings at runtime to store all text files in appropriate strings"

Try this:

OpenFileDialog ofd = new OpenFileDialog();
ofd.Multiselect = true;
if (ofd.ShowDialog() == DialogResult.OK)
    {
    List<string> data = new List<string>();
    foreach (string file in ofd.FileNames)
        {
        data.Add(File.ReadAllText(file));
        }
    }

或者如果您更喜欢Linq：

Or this if you prefer Linq:

OpenFileDialog ofd = new OpenFileDialog();
ofd.Multiselect = true;
if (ofd.ShowDialog() == DialogResult.OK)
    {
    string[] data = ofd.FileNames.Select(f => File.ReadAllText(f)).ToArray();
    }

您可以从文本文件中读取内容如下：

You can read the content from a text file as the follows:

String yourFileFromDialog = "file location and file name";
String textFromFile = string.Empty;

try
{
   using (StreamReader sr = new StreamReader(yourFileFromDialog))
   {
       textFromFile = sr.ReadToEnd();
   }
}
catch (Exception e)
{
   //exception handling
}

这里 [ ^ ]你可以阅读更多。



如果您的文件名有字符串数组，请执行以下操作：

Here[^] you can read more.

If you have a string array for your file names, do the follow:

string[] fileNames = //fill up from your dialog

String yourFileFromDialog = string.Empty,
       textFromFile = string.Empty;

try
{
   for(int i = 0; i < fileNames.length; i++)
   {
      yourFileFromDialog = fileNames[i];
    
      using (StreamReader sr = new StreamReader(yourFileFromDialog))
      {
         textFromFile += sr.ReadToEnd();
      }     
   }

}
catch (Exception e)
{
   //exception handling
}

对于以后使用文件中的文本，您可以为您的类创建一个私有属性，并将其替换为textFromFile变量：

For the later usage of the text from the files you can make a private property to your class and append this instead of textFromFile variable:

private string textFromFiles = string.Empty; 

Chk此代码：

Chk this code :

 System.IO.StreamReader file = new System.IO.StreamReader(@"D:\test.txt");
String Line="";
String txtLine = "";
while ((Line = file.ReadLine()) != null)
{
    txtLine = txtLine + Line;
  
}
file.Close();
            textBox4.Text=txtLine;

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