C＃Getter / Setter无法正常工作

Question

I am rather the Java-Guy, so handling getters/setters in C# is a little new to me. Why is this not working?

public String lastmodified {
            get { return this.lastmodified; }
            set 
            { 
                long ms = Int64.Parse(value);
                var date = new DateTime(1970, 1, 1).AddSeconds(ms);
                date.ToLocalTime();
                this.lastmodified = date.ToString("HH_mm_yyyy");
            }
        }

value is in this cade a String which goes like 1987123019

Answer 1

Because you are assigning property itself on the last line. You should use either different casing or underscores to distinguish properties or fields.

I would recommend standard C# naming conventions. Also save the data in their native format. And also what driis said.

private DateTime lastModified;
public String LastModified {
        get { return lastModified.ToString("HH_mm_yyyy"); }
        set 
        { 
            long ms = Int64.Parse(value);
            var date = new DateTime(1970, 1, 1).AddSeconds(ms);
            date = date.ToLocalTime();
            lastModified = date;
        }
    }

Answer 2

This will get you a StackOverflowException, since you are calling the property setter recursively in the last line of set (and get , for that matter). You need to assign the value to a field of a class, and read it from that field in the getter. Your current code simply calls into the same property accessor method infinitely, until you run out of stack space.

Common C# naming conventions suggests PascalCasing for property and method names, and camelCasing for instance variables, possibly prefixed with an underscore.

This code should work:

private string lastModified; // instance variable
public string LastModified 
{
    get { return this.lastModified; }
    set 
    { 
        long ms = Int64.Parse(value);
        var date = new DateTime(1970, 1, 1).AddSeconds(ms);
        date = date.ToLocalTime();
        this.lastModified = date.ToString("HH_mm_yyyy");
    }
}

Also, "Not working" is kind of broad; but I am going to guess that you will see that the ToLocalTime method does not get applied to the date. This is because DateTime in C# is immutable, so it cannot be changed after construction. You will need to assign your date variable to the result of ToLocalTime() :

date = date.ToLocalTime();

Answer 3

For a property procedure, the getter should return the value of the class member variable holding the "wrapped" value. For a setter, the inbound value should be assigned to that class member variable. What you're doing makes the property self-referential.