我正在尝试创建一个上传文件按钮，但每当我尝试使用文件时，我都会收到错误“空路径名称不合法”

Question

Every time I click on a file, I get the error

Empty path name is not legal

I need a user to upload a .txt or .csv file and have the contents of that file to display in the data grid view. Everything works fine except for this one error that occurs on this line:

var sr = new StreamReader(openFileDialog1.FileName);

Full code.

private void selectButton_Click (object sender, EventArgs e)
{
    if (openFileDialog1.ShowDialog() == DialogResult.OK)
    {
        try
        {
            var sr = new StreamReader(openFileDialog1.FileName);
            SetText(sr.ReadToEnd());
        }
        catch (SecurityException ex)
        {
            MessageBox.Show($"Security error.\n\nError message{ex.Message}\n\n" +
                $"Details:\n\n{ex.StackTrace}");
        }
    }
}

Answer 1

尝试在openFileDialog1上添加过滤器之类的。

openFileDialog1.Filter = "text file(*.txt)|*.txt|csv file(*.csv)|*.csv";

Answer 2

Check the FileName before open file:

if (openFileDialog1.ShowDialog() == DialogResult.OK)
    {
        if (string.IsNullOrEmpty(openFileDialog1.FileName) {
            // ..
            return; 
        }

        try
        {
            var fileStream = openFileDialog1.OpenFile();

            using (StreamReader reader = new StreamReader(fileStream))
            {
                SetText(sr.ReadToEnd());
            }       
        }
        catch (SecurityException ex)
        {
            MessageBox.Show($"Security error.\n\nError message{ex.Message}\n\n" +
                $"Details:\n\n{ex.StackTrace}");
        }
    }