Chapter 13 eg. TextBoxTest age TextBox changed

guyhuang · January 22nd, 2004, 10:16 AM

follow the code on the book we can build a program which can avoid typing wrong messages.
but the age TextBox has some problems.
if you type the ALL-RIGHT messages in each TextBox and then post some words in the age TextBox using the right click menu, it's OK.
so we get:

Code:

Name:Guyhuang
Address:Wuhan,
Hubei,
China.
Occupation:Programmer
Age:Programmer

the false is the function txtBox_TextChanged(object sender, EventArgs e).
we must check the changed text in txtAge TextBox to see if it is still a number.
but HOW.

i am a c# programmer learner in china.
hope to communicate with you.

guyhuang · January 22nd, 2004, 10:28 AM

i found a way to solve this problem but is not very suitable.
if we can check string as a number, code will be simple.
that's code adding before the else in the function private void txtBox_TextChanged(object sender, EventArgs e)

Code:

            else if(tb==txtAge)//if tb==txtAge,avoiding any char that isnot num
            {
                char[] charArray;
                charArray=tb.Text.ToCharArray();
                bool isNum=true;
                foreach(char c in charArray)
                {
                    if(c<48||c>57)
                        isNum=false;
                }
                if(isNum==false)
                {
                    tb.Tag=false;
                    tb.BackColor=Color.Red;
                }
            }

i am a c# programmer learner in china.
hope to communicate with you.