Adding Integer from textbox to database c#

Question

I'm a newbie to c# and am having some difficulty getting an integer from a textbox to a database.

I have created a simple form which allows a user to input their firstName, lastName, and age.

I can connect the firstName and lastName to the database on a buttonClick, but am unable to to the same with age. Here is what I have.

   private void AddTheNewInfoToDB()
    {
        using (DatabaseContainer db = new DatabaseContainer())
        {
            Users u = new Users();

            u.firstName = textboxfirstName.Text;
            u.lastName = textboxlastName.Text;
            u.Age = textboxAge.Text; 


            db.Users.AddObject(u);
            db.SaveChanges();
        }

When I do this, I get an error for the "textboxAge.Text" which says "Cannot implicitly convert tye 'string' to 'int'."

Advice on fixing this would be appreciated.

walther · Accepted Answer · 2012-06-27 22:32:50Z

2

u.Age = Int32.Parse(txtboxAge.Text);

You're having a problem, because were trying to assign a string (.Text) to a variable of type Int (Age).

answered Jun 27, 2012 at 22:32

walther

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2 Comments

Nathan Over a year ago

This will work but keep in mind that textboxAge.Text may not be constrained to just numbers. If it contains invalid characters it will throw a FormatException

walther Over a year ago

@Nathan, sure, but one should apply validation logic 24/7. If he does, there's no need to apply additional checks in db access layer to verify the data again.

code4life · Accepted Answer · 2012-06-28 15:05:25Z

1

Try:

int age;
int.TryParse(textboxAge.Text, out age); 
u.Age = age;

edited Jun 28, 2012 at 15:05

answered Jun 27, 2012 at 22:32

code4life

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8 Comments

Nathan Over a year ago

This is wrong. It should be int.TryParse(textboxAge.Text, out age); and it wont set age to 0 age will remain as it was, point of fact 0.

walther Over a year ago

You consider a good habit to repair a bad input? Because that's exactly what you're doing. If the user provides a bad input (e.g. a string), you should notify him and NOT allow him to post to db. But instead, you've decided it's valid for someone to have age = 0 and actually update the db?

code4life Over a year ago

@walther: you do your validation together with the actual database operation? I'd imagine the validation should be done BEFORE the post to db actually takes place. Also, regardless of the validation trifle, TryParse is still the most efficient way to do this.

code4life Over a year ago

@Nathan: I invite you to review this in Reflector. I'm sure you'll realize that what you just said is in fact, untrue. The TryParse will set the out variable to 0 before reporting a boolean result.

walther Over a year ago

@code4life, precisely, validation should be done BEFORE. That means when you're doing the insert/update, you already know it contains an integer within a specified range = you don't have to tryparse, simple parse will do. Why do you consider it superior to parse in this particular case?

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kmatyaszek · Accepted Answer · 2012-11-15 06:07:23Z

0

use int.parse(textboxAge.Text);

edited Nov 15, 2012 at 6:07

kmatyaszek

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answered Jun 27, 2012 at 22:33

Ryan Durrant

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