[c#] Cannot implicitly convert type 'string' to 'System.Threading.Tasks.Task<string>'

I am new to asynchronous programming, so after going through some async sample codes, I thought of writing a simple async code

I created a simple Winform application and inside the Form I wrote the following code. But its just not working

private Task<string> methodAsync() {
    Thread.Sleep(10000);
    return "Hello"; //Error: Cannot implicitly convert type 'string' to 'System.Threading.Tasks.Task<string>'
}

private async void button1_Click(object sender, EventArgs e)
{
    string s = await methodAsync();
    MessageBox.Show(s);
}

Could someone please put some light here..

Use FromResult Method

public async Task<string> GetString()
{
   System.Threading.Thread.Sleep(5000);
   return await Task.FromResult("Hello");
}

Beyond the problematic use of async as pointed out by @Servy, the other issue is that you need to explicitly get T from Task<T> by calling Task.Result. Note that the Result property will block async code, and should be used carefully.

Try:

private async void button1_Click(object sender, EventArgs e)
{
    var s = await methodAsync();
    MessageBox.Show(s.Result);
}

    //source    
    public async Task<string> methodName()
            {
             return Data;
             }

    //Consumption
     methodName().Result;

Hope this helps :)