C# Check if a user typed a number into a textbox.

[Keevu]

Code: Select all

if(IsNumeric(textBox1.Text) == true)
  {
     // your convert code goes here
  }
  else
  {
     // your error message goes here
  }

put something like "please input number" where the your error message goes where comment is at.

snippet made by the great edward. I take no credit.

[dandymcgee]

Lol, wow. That was simple enough.

[trufun202]

Code: Select all

if(IsNumeric(textBox1.Text) == true)
  {
     // your convert code goes here
  }
  else
  {
     // your error message goes here
  }

put something like "please input number" where the your error message goes where comment is at.

snippet made by the great edward. I take no credit.

actually..that's not correct. .NET doesn't have an IsNumeric() method built into the framework. That's an old VB method that didn't make it in the jump to .NET.

I would recommend the following:

Code: Select all

int number = 0;

if (int.TryParse(textBox1.Text, out number))
{
    //do something with number
}
else
{
    //scream at the user, cuz that's not a number!
}

EDIT: Or, a more user friendly option may be to use an asp:RegularExpressionValidator to validate the number on the client side.

[Keevu]

Code: Select all

if(IsNumeric(textBox1.Text) == true)
  {
     // your convert code goes here
  }
  else
  {
     // your error message goes here
  }

put something like "please input number" where the your error message goes where comment is at.

snippet made by the great edward. I take no credit.

actually..that's not correct. .NET doesn't have an IsNumeric() method built into the framework. That's an old VB method that didn't make it in the jump to .NET.

I would recommend the following:

Code: Select all

int number = 0;

if (int.TryParse(textBox1.Text, out number))
{
    //do something with number
}
else
{
    //scream at the user, cuz that's not a number!
}

EDIT: Or, a more user friendly option may be to use an asp:RegularExpressionValidator to validate the number on the client side.

thanks this helped it works very well.

[Apoc]

Use decimal.TryParse unless you want to force non-floating-point numbers on the user. (In which case; I'd still use a larger datatype. long.TryParse for instance)

Also, don't use TryParse unless you're absolutely sure you want to suppress exceptions. (In simple cases like this, it's fine. In most other cases, avoid it wherever possible.)