Task.Run 出现异步方法错误

Question

i have button1_click method like this

 private async void button1_Click(object sender, EventArgs e)
    {


        Task<string> st1 = Task.Run(() => ReadFromFile());
        textBox1.AppendText("sdsadsa");
        textBox1.Text = st1.Result;



    }

i want to read from text file with ReadFromFile()

Note: ReadFromFile is marked with async because i want to use async and await in this method

to planning some Task methods

but my Ui is freezing after append text method calling in line 2 in my button1_click method

and wait the result and show it in text box.

i want to throw the ReadFromFile method in task and await it without ui freezing

i tried many things like replacing line 1 with this

Task<string> st1 = await Task.Factory.StartNew(() => ReadFromFile());

with this, ui dont freeze but it skips line 2 the append method, i dont know why this skiping?

Answer 1

Just await ReadFromFile:

private async void button1_Click(object sender, EventArgs e)
{
    string st1 = await ReadFromFile();
    textBox1.AppendText("sdsadsa");
    textBox1.AppendText(st1);
}