how to check if numbers and letters are entered in a textbox

[katy_price]

how do i check textboxes to see whether the user has entered letters, symbols and/or integers? My program requires the user to enter atleast one numeric value, if they don't enter atleast one number then an error message will show. i have tried the following but had no luck:

// checks password for letters

private: System::Boolean ValidateInput()

{

if (password != "0-9")
{
ShowMessage("password must contain atleast one numeric value (0-9).");
// clear text boxes
txtPassword->Text = "";
txtRePassword->Text = "";
}
}

any help will be appreciated thanks