从类访问表单控件？

Question

I have a Get Status button on my form and the code for that currently looks like this:

private void btnGetStatus_Click(object sender, EventArgs e)
    {
        // Check if a runner has been selected
        if (lstRunners.SelectedIndex > -1)
        {
            // Obtain selected runner
            Runner selectedRunner = (Runner)lstRunners.SelectedItem;

            // Call the method in Runner class to get the runner's status
            selectedRunner.GetStatus(selectedRunner);
        }
    }
}
}

Now in the Runner class I have:

public void GetStatus(Runner selectedRunner)
    {
        if (selectedRunner.HasFinished == true)
        {
            lblRunnerInfo.Text = "Runner has already finished!";
        }
    }

What I'm basically trying to do is make the btnGetStatus call the GetStatus method in the Runner class and what I want that method to do is then basically check the boolean HasFinished to see if the runner has finished and if they have finished, the lblRunnerInfo.Text has a message to reflect this and if the boolean is false, then basically output a message saying "Runner has not yet finished / did not finish"

I'm not quite sure if it's proper practice to access form controls from a class or if it even can be done, but I am not sure of how to do it the way I want (Getting the GetStatus method to check the status of the runner rather than getting the btnGetStatus to fire the code.)

Answer 1

I think what you're looking for is this:

lblRunnerInfo.Text = selectedRunner.GetStatus();

and then in the runner class:

public string GetStatus()
{
    if (this.HasFinished == true)
    {
        return "Runner has already finished!";
    }
    return "Finished";
}

Answer 2

You can change the btnGetStatus_Click as follows:

private void btnGetStatus_Click(object sender, EventArgs e)
{
    // Check if a runner has been selected
    if (lstRunners.SelectedIndex > -1)
    {
        // Obtain selected runner
        Runner selectedRunner = (Runner)lstRunners.SelectedItem;
        // Call the method in Runner class to get the runner's Status
        // CHANGED
        if (selectedRunner.HasFinished)
            lblRunnerInfo.Text = "Runner has already finished";
    }
}

This way, the form handles the output and the Runner class is responsible for "running". If you have a more complex Status Situation later on, then you still can add an enumeration for the states and retrieve the Status instead of just checking for HasFinished. To retrieve the text, you need to add a mapping from the Status enumeration to the appropriate text.

Answer 3

Why not just access your HasFinished() property directly?

    private void btnGetStatus_Click(object sender, EventArgs e)
    {
        // Check if a runner has been selected
        if (lstRunners.SelectedIndex > -1)
        {
            // Obtain selected runner
            Runner selectedRunner = (Runner)lstRunners.SelectedItem;

            // Call the method in Runner class to get the runner's status
            if (selectedRunner.HasFinished)
            {
                lblRunnerInfo.Text = "Runner has already finished!";
            }
            else
            {
                lblRunnerInfo.Text = "Runner has NOT finished yet!";
            }
        }
    }

Answer 4

how about something like this

private void btnGetStatus_Click(object sender, EventArgs e)
{
    // Check if a runner has been selected
    if (lstRunners.SelectedIndex > -1)
    {
        // Obtain selected runner
        Runner selectedRunner = (Runner)lstRunners.SelectedItem;

        // Call the method in Runner class to get the runner's status
        lblRunnerInfo.Text = selectedRunner.GetStatus(selectedRunner);
    }

}

then set your GetStatus as string

public string GetStatus(Runner selectedRunner)
{
    if (selectedRunner.HasFinished == true)
    {
        return "Runner has already finished!";
    }
}