修改/替换在c＃中的tab-base文本文件中

Question

这个问题是过去讨论的延续。因此，现在我设法读取了文本文件中的每一行，并读取特定列中的精确字符串。我现在的问题是，我希望用另一个字符串值修改Tab-Base文件的第（4）列中的文本值。例如，原始文件是这样的：

ID1 25  800 Low
ID2 25  700 Low
ID3 25  600 Low

我想更改为：

ID1 25  800 High
ID2 25  700 High
ID3 25  600 High

…这是我的完整代码。感谢您的帮助。

string route = @"C:MyFile.txt";
FileStream fileStream2 = new FileStream(route, FileMode.Open);
var m_readFile2 = new StreamReader(fileStream2);
var m_writeFile2 = new StreamWriter(fileStream2);
        string[] colArr1 = new string[100];
        string[] colArr2 = new string[100];
        string[] colArr3 = new string[100];
        string[] colArr4 = new string[100];
        int arrcount = 1;
        while ((line = m_readFile2.ReadLine()) != null)
        {
            string col1 = "";
            string col2 = "";
            string col3 = "";
            string col4 = "";
                col1 = line.Split('t')[0];
                col2 = line.Split('t')[1];
                col3 = line.Split('t')[2];
                col4 = line.Split('t')[3];
                colArr1[arrcount] = col1;
                colArr2[arrcount] = col2;
                colArr3[arrcount] = col3;
                colArr4[arrcount] = col4;    

                m_writeFile2.WriteLine("Serv" + arrcount  + "t" + "25" + "t" + "400" + "t" + "High");
                arrcount = arrcount + 1;

Answer 1

亲吻

string text = File.ReadAllText(route);
text = text.Replace("Low", "High");
File.WriteAllText(route, text);

Answer 2

我建议您将行分为数组，然后将新线路放回原处：

        string source = @"D:MyFile.txt";
        string destination = @"D:MyFile2.txt";
        int columnToChange = 3;
        string newValueForColumn = "High";
        using (FileStream sourceStream = new FileStream(source, FileMode.Open))
        {
            using (FileStream destinationStream = new FileStream(destination, FileMode.CreateNew))
            {
                using (StreamReader sourceReader = new StreamReader(sourceStream))
                {
                    using (StreamWriter destinationWriter = new StreamWriter(destinationStream))
                    {
                        string oldLine = string.Empty;
                        while ((oldLine = sourceReader.ReadLine()) != null)
                        {
                            string[] values = oldLine.Split('t');
                            StringBuilder newLine = new StringBuilder();
                            if (values.Length > columnToChange)
                            {
                                values[columnToChange] = newValueForColumn;
                                for (int i = 0; i < values.Length; i++)
                                {
                                    newLine.Append(values[i]);
                                    if (i + 1 < values.Length)
                                    {
                                        newLine.Append('t');
                                    }
                                }
                            }
                            else
                            {
                                newLine.Append(oldLine);
                            }
                            destinationWriter.WriteLine(newLine.ToString());
                        }
                    }
                }
            }
        }
        // File.Delete(source);
        File.Move(source, source + ".bak");
        File.Move(destination, source);
    }

Answer 3

    //Works fine Thomas Voß  - I've just added a line to ensure that Column Header is 
    //also not changed
    string source = @"D:MyFile.txt";
    string destination = @"D:MyFile2.txt";
    int columnToChange = 3;
    string newValueForColumn = "High";
    using (FileStream sourceStream = new FileStream(source, FileMode.Open))
    {
        using (FileStream destinationStream = new FileStream(destination, FileMode.CreateNew))
        {
            using (StreamReader sourceReader = new StreamReader(sourceStream))
            {
                using (StreamWriter destinationWriter = new StreamWriter(destinationStream))
                {
                    string oldLine = string.Empty;
                    while ((oldLine = sourceReader.ReadLine()) != null)
                    {
                        string[] values = oldLine.Split('t');
                        StringBuilder newLine = new StringBuilder();
                        if (values.Length > columnToChange)
                        {
                            if (values[columnToChange] != "ColumnHeaderName")
                            {
                               values[columnToChange] = newValueForColumn;
                            }
                            for (int i = 0; i < values.Length; i++)
                            {
                                newLine.Append(values[i]);
                                if (i + 1 < values.Length)
                                {
                                    newLine.Append('t');
                                }
                            }
                        }
                        else
                        {
                            newLine.Append(oldLine);
                        }
                        destinationWriter.WriteLine(newLine.ToString());
                    }
                }
            }
        }
    }
    // File.Delete(source);
    File.Move(source, source + ".bak");
    File.Move(destination, source);
}