任何人都能告诉我下面的错误提供者代码之间的差异吗？

Question

IDE: Visual Studio 2010, C# .net application,winforms

I am really surprised that this code Code-1 works fine

    ErrorProvider ef = new ErrorProvider();
    private void textBox1_TextChanged(object sender, EventArgs e)
    {
        if (textBox1.Text == string.Empty)
        {
            ef.SetError(textBox1, "asdf");
        }
        else
        {
            ef.Clear();
        }
    }

but this code Code 2 :

    private void textBox1_TextChanged(object sender, EventArgs e)
    {
        ErrorProvider ef = new ErrorProvider(); //changes is here
        if (textBox1.Text == string.Empty)
        {
            ef.SetError(textBox1, "asdf");
        }
        else
        {
            ef.Clear();
        }
    }

is not working ie its not providing me error handling facility. can anyone tell me the exact reason what is the difference between these two codes. and why the 2nd code is not working fine..

Answer 1

在code1中，您在事件处理程序范围之外创建ef对象，并且在处理事件之后ef对象仍然存在，其中在code2中 ， ef对象在处理事件后被销毁。