c＃-无法备份mysql数据库，错误为“不支持给定路径的格式。”

Question

private void Backup()
    {
        string x = txtb.Text; 
        string date = DateTime.Now.ToString("MM-dd-yyyy HH:mm:ss");
        string file = x + date + "database backup.sql";
        string conn = "server = localhost; user id = root; password =; database = sais_db;";

        try
        {
            MySqlBackup mb = new MySqlBackup(conn);
            mb.Export(file);
            MessageBox.Show("Database Backup Success!");
        }

        catch (MySqlException ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

Help please, when I run my program, I get a NotSupportedException error. How do I fix it?

PS txtb.Text contains directory path like this C:\\Users\\user\\Desktop

Answer 1

Your DateTime format includes colons. Those are not allowed in a file or pathname except for delimiting the drive letter from the path.

You can easily fix that by changing the format string of your DateTime.Now call:

string x = txtb.Text; 
string date = DateTime.Now.ToString("MM-dd-yyyy HH-mm-ss");
string file = x + date + "database backup.sql";

When you run this you'll get (assumimg txtb.Text contains foo ) in file

foo09-24-2016 14-20-59database backup.sql

You can also consider to do that in one go:

string file = String.Format(
    "{0}{1:MM-dd-yyyy HH-mm-ss}database backup.sql", 
    txtb.Text,
    DateTime.Now);

If you allow your users to provide (part of) a filename consider checking for invalid characters. The Path class in the System.IO namespace has a nice helper for that GetInvalidFileNameChars .

if (file.IndexOfAny(Path.GetInvalidFileNameChars()) > -1) 
{
    // show an error
    MessageBox.Show("invalid characters in file");
   return;
}

There is a similar method for InvalidPathChars