如何使用按钮验证c＃中文本框的内容？

Question

Hi a GUI that lets the user input a few different types of data. How do I go about validating the user input so that it is not blank and for some values to check if it is within a range of numbers?

Answer 1

For not blank values, you merely need to check whether string.IsNullOrWhiteSpace(value) returns true or false.

For an integer range check if value<=100 && value>=0

For the date, check if DateTime.TryParseExact(value, "MM/dd/yyyy", CultureInfo.InvariantCulture, DateTimeStyles.None, out parsed) is true or false

Answer 2

You can create IsValid (or something like this) method inside your Student class (I assume that student1 is object of class Student ):

class Student
{
    // your code
    // ...
    public bool IsValid()
    {
        bool isValid = true;

        if(string.IsNullOrWhiteSpace(FirstName))
        {
           isValid = false;
        }
        else if(string.IsNullOrWhiteSpace(LastName))
        {
           isValid = false;
        }
        // ... rest of your validation here

        return isValid;
    }
}

and later:

private void button1_Click(object sender, EventArgs e)
{
    student1.FirstName = firstnamebox.Text;
    student1.SecondName = secondnamebox.Text;
    student1.DateofBirth = DateTime.Parse(dobtextbox.Text).Date;
    student1.Course = coursetextbox.Text;
    student1.MatriculationNumber = int.Parse(matriculationtextbox.Text);
    student1.YearMark = double.Parse(yearmarktextbox.Text);

    if(student1.IsValid())
    {
        // good
    }
    else
    {
        // bad
    }
}

Answer 3

For validation in windows control, please go through following articles

Validators for Windows Forms - ValidationProvider Control

User Input Validation in Windows Forms

Using Error Provider Control in Windows Forms and C#

For web forms.

Validation Controls in Web Forms