执行代码string csvFileName = Path.Combine(@"E:\report", fileName + ".csv"); if (File.Exists(csvFileName)) { File.Delete(csvFileName); } using (StreamWriter sw = new StreamWriter(csvFileName, true, Encoding.UTF8)) 表头{ sw.WriteLine("Test Model： " + exParams.GetParameter("Model") + "--特斯拉烧录系统"); sw.WriteLine("Software Version： " ); sw.WriteLine("Serial Number: " + barcode); sw.WriteLine("Start Time: " ); sw.WriteLine("Test Time: " + testTime); sw.WriteLine("Test Result: " + result); sw.WriteLine("Test Operator: " ); sw.WriteLine("Test Equipment Number: " + exParams.GetParameter("E_NO")); sw.WriteLine("Burnprocess: " + exParams.GetParameter("Process")); sw.WriteLine("************************************************************************************************************************"); } }在转换后，之前的txt文件内容不见了，只剩添加的表头了。在此基础上改，先转换，再将表头添加到csv文件中，txt文件内容紧随其后

可以尝试以下代码：

string txtFileName = Path.Combine(@"E:\report", fileName + ".txt");
string csvFileName = Path.Combine(@"E:\report", fileName + ".csv");

if (File.Exists(csvFileName)) {
    File.Delete(csvFileName);
}

// 读取txt文件内容
string txtContent = File.ReadAllText(txtFileName, Encoding.UTF8);

using (StreamWriter sw = new StreamWriter(csvFileName, true, Encoding.UTF8)) {
    // 先写入表头
    sw.WriteLine("Test Model： " + exParams.GetParameter("Model") + "--特斯拉烧录系统");
    sw.WriteLine("Software Version： ");
    sw.WriteLine("Serial Number: " + barcode);
    sw.WriteLine("Start Time: ");
    sw.WriteLine("Test Time: " + testTime);
    sw.WriteLine("Test Result: " + result);
    sw.WriteLine("Test Operator: ");
    sw.WriteLine("Test Equipment Number: " + exParams.GetParameter("E_NO"));
    sw.WriteLine("Burnprocess: " + exParams.GetParameter("Process"));
    sw.WriteLine("************************************************************************************************************************");

    // 写入txt文件内容
    sw.WriteLine(txtContent);
}

首先读取原来的txt文件内容，然后将表头和txt文件内容一起写入到csv文件中。注意添加了`true`参数，表示以追加方式写入文件。