Calling a Method From a Form

[dburris]

Hello, I am attempting to call a method from a click event on a form and not having much luck.

public void xbuttonValidateUPC_Click(object sender, EventArgs e)
{//Validate UPC Button Click
UPC_JDB UPC1 = new UPC_JDB("123");
string temp = (xtextBoxValidate.Text);
UPC1.ValidateUPC(temp);
xtextBoxValidateAnswer.Text = temp;
}//end Validate UPC Button Click

Program is supposed to take a string value in xtextBoxValidate text box, send it to ValidateUPC, and get back a message to display in xtextBoxValidateAnswer text box whether the UPC code is valid or not. At this point it just puts whatever I put in xtextBoxValidate.Text into xtextBoxValidateAnswer.Text. Any ideas?

[thines01]

Did you wrote the UPC1.ValidateUPC()?
If so, is the parameter that takes the "temp" a (ref string ...)?
Does it take a reference to a string (if you expect the string to be modified)?

[dburris]

Did you wrote the UPC1.ValidateUPC()?
If so, is the parameter that takes the "temp" a (ref string ...)?
Does it take a reference to a string (if you expect the string to be modified)?

Yes, I created UPC1.ValidateUPC(). Yes, the paramter that takes the temp variable is a string. Yes, it does take a reference to a string. It works in console but trying to get it working in a form has eluded me so far. I pretty much too the code from the console version and modified it for the form.

Here is the console version that works just fine.:

UPC_JDB UPC1 = new UPC_JDB("123");
Console.Write("Enter UPC to be validated: ");
string temp = Console.ReadLine();
Console.Write(UPC1.ValidateUPC(temp));
Console.ReadLine();

[thines01]

Have you stepped through this in the debugger to see that the correct value is being passed?

[dburris]

I was able to walk through the program and ValidateUPC is definitely getting the string variable and processing it properly. The problem I believe is in the return.

Here is the code for the return in ValidateUPC.

if (CheckSum != num12)
           {
               return "The UPC checksum is invalid"; 
           }
           else
           {
               return "The UPC checksum is valid";
           }

I was assuming the return string value of temp would be either "The UPC checksum is invalid" or "The UPC checksum is valid". It doesn't appear anything is returning from ValidateUPC.

[thines01]

No, you're not actually modifying "temp" with that type of function.
What you should do (if you want to keep it the way you have it is):

xtextBoxValidateAnswer.Text = UPC1.ValidateUPC(temp);

[dwarvenassassin]

Console.Write(UPC1.ValidateUPC(temp)); writes the output from the function to the console whereas UPC1.ValidateUPC(temp); never saves the output for later display.
I suspect your Validate rountine is coded using "pass by value" rather than "pass by reference" - partly because a routine using ref wouldn't actually need a returned value.