在 C# 中修改/替换基于选项卡的文本文件中的文本

Question

这个问题是过去讨论HERE 的延续。所以现在我设法读取了我的文本文件中的每一行，并读取了某一列中的确切字符串。我现在的问题是，我希望用另一个字符串值修改 tab-base 文件的列 (4) 中的文本值。 比如原来的文件是这样的：

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

我想改成：

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

我建议您将这些行拆分为一个数组并重新组合一个新行：

        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 2

KISS

string text = File.ReadAllText(route);

text = text.Replace("Low", "High");

File.WriteAllText(route, text);

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);
}