將savedialog的文件名追加到將要保存的文件

Question

我想在要保存的文本文件的第一行添加文件的名稱。我該怎麼做？這是一個代碼。我找不到一個方法讓stringbuilder在其實例的開始處追加。

StringBuilder sb = new StringBuilder(); 

sb.AppendLine("BLAH BLAH"); 

if (saveFile.ShowDialog() == DialogResult.OK) 
{ 
    //How to append file name at the beggining of the file to be saved? 

    File.WriteAllText(saveFile.FileName, sb.ToString()); 
} 

謝謝。

Answer 1

你打電話之前WriteAllText添加此行：

sb.Insert(0, saveFile.FileName + Environment.NewLine); 

- 或 -

string outString = saveFile.FileName + Environment.NewLine + sb.ToString(); 
File.WriteAllText(saveFile.FileName, outString); 

Answer 2

要保留以前的文本：

StringBuilder sb = new StringBuilder(); 

// Appending string to your StringBuilder string value. 
sb.AppendLine("BLAH BLAH"); 

if (saveFile.ShowDialog() == DialogResult.OK) 
{ 
    // Keep the previous file text .. By inserting it in the begining of the 
    // StringBuilder string value. 
    sb.Insert(0, File.ReadAllText(saveFile.FileName) + Environment.NewLine); 

    // Insert File Name in the begining of the StringBuilder string value. 
    sb.Insert(0, saveFile.FileName + Environment.NewLine); 

    File.WriteAllText(saveFile.FileName, sb.ToString()); 
}