c# - 从文件加载错误c#

Question

我正在做数学测验，我成功地将我的问题和答案保存在不同的文件中。现在我正在尝试将我的问题从我的文件中加载到标签中。我会将文件的每一行加载为一个不同的问题。

这是我保存文件的方式:

//checking if question or answer textbox are empty. If they are not then the question is saved

if (txtquestion.Text != "" & txtanswer.Text != "") {
  //saves the question in the questions text
  using (System.IO.StreamWriter file = new System.IO.StreamWriter(@"C:\Users\User\Desktop\Assignment 2 Solo part\Questions.txt", true)) {
    file.WriteLine(txtquestion.Text);
  }
  //saves the answer in the answers text
  using (System.IO.StreamWriter file = new System.IO.StreamWriter(@"C:\Users\User\Desktop\Assignment 2 Solo part\Answers.txt", true)) {
    file.WriteLine(txtanswer.Text);
  }
  MessageBox.Show("Question and Answer has been succesfully added in the Quiz!", "Success!", MessageBoxButtons.OK, MessageBoxIcon.None);
  //cleaning the textboxes for a new question and answer
  txtanswer.Text = "";
  txtquestion.Text = "";
} else if (txtquestion.Text == "")
//checks if the question textbox is empty and shows the corresponding message
  else if (txtquestion.Text == "")
    MessageBox.Show("Please enter a question", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
  else  //checks if the answer textbox is empty and shows the corresponding message
    if (txtanswer.Text == "")
      MessageBox.Show("Please enter an answer", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);

这就是我尝试加载问题的方式:

private void frmquestion_Load(object sender, EventArgs e) {
  string line;
  string[] file = System.IO.File.ReadAllLines(@"C:\Users\User\Desktop\Assignment 2 Solo part\Questions.txt");
  line = file.ReadLine();
  Console.WriteLine(line);
}

我得到的错误是:

'System.Array' does not contain a definition for 'ReadLine' and no extension method 'ReadLine' accepting a first argument of type 'System.Array' could be found (are you missing a using directive or an assembly reference?)

Answer 1

File.ReadAllLines方法将文件的所有行读入一个字符串数组。所以你有一个字符串数组，但你将它命名为 file，为变量使用有意义的名称将增加代码的可读性。

 string[] lines = System.IO.File.ReadAllLines(@"C:\Users\User\Desktop\Assignment 2 Solo part\Questions.txt");

现在，如果您需要打印每一行，则必须循环遍历字符串数组。

foreach(var line in lines)
   Console.WriteLine(line);

还有一些与您的问题无关但与您的编码有关的事情

if (txtquestion.Text != "" & txtanswer.Text != "") {

在这里您可以使用 string.IsNullOrEmpty() 方法来检查空字符串，如下所示

if (!string.IsNullOrEmpty(txtquestion.Text) && !string.IsNullOrEmpty(txtanswer.Text)) {

请注意，您需要使用 && 作为 AND 运算符