there is a different between comma(,) and dot(.) in checking a "Double" data type.
I trying to input this wrong value for the "Double" data type.
A form with method="get" How to interact with the user, with the Request. A form with method="post" How to interact with the user, with the Request. A form with radio buttons How to interact with the user, through radio buttons, with the Request. Information sent from a form with the GET method is visible to everyone (it will be displayed in the browser's address bar) and has limits on the amount of information to send. Form command is used to collect values in a form with method="post".
Query String command is used to collect values in a form with method="get".
This is because a good portion of program errors come from unexpected user input or responses.
For example, what do you think would happen if a user entered a letter or character as an operand into a math quiz game?
A better question is, "How do I prevent a user from entering a letter into a text box intended for numbers?
" What about a game that prompts a user for a level; would testing that the input is a number be enough?
If your textbox contains things like "..." and you try to convert that to a double, you will get an error. First, to solve the conundrum presented by DDanbe, you need to use a Masked Textbox and set a custom mask using as many numbers and you want on the left then a decimal point and then as many as you want on the right. Next you have to parse the input from string to strings to numbers to number like so: Notably, the code is ugly because I wrote it fast for an example, but it works (and that's what matters). To Double(percent_str) new_percent /= 10 ^ A ' convert the whole number into its correct percentage of 1 Dim total_number As Double = new_number new_percent Msg Box(total_number) End Sub Public Class Form1 Private Sub Button1_Click(sender As System. Text ' holds user input provided from Masked Input Box Dim _Count As Integer = str_input.
NET tutorials that are easy to follow and simple to implement.
Form validation is important […] is responsible for bringing you an exhaustive list of ASP.
Holds numbers after "." is found For X As Integer = 0 To _Count - 1 ' Parse the whole numbers out now If (str_input(X) " ") Then ' Parse the whole numbers and remove spaces then the decimal point str_number(X) = str_input(X) Else If (str_input(X) = ".") Then num_len = X ' whole numbers equals how many iterations before we found "." Go To PARSE_POINT End If If (0 = 1) Then PARSE_POINT: str_Decimal = str_input(X) ' 'parse the decimal point out now Dim dec_place As Integer = X ' the decimal point is found where the 'X' For stopped iterating to come here For Y As Integer = 0 To (_Count - (X 1)) ' parse the percentage portion out now (Count is total and X 1 is where the decimal numbers start) If (str_input(Y dec_place) " ") Then str_Percent(Y) = str_input(Y dec_place) ' only use the numbers after the decimal point per_len = Y ' Y is equal to number of decimals processed End If Next End If Next Dim number_str As String Dim percent_str As String For T As Integer = 0 To num_len ' set whole numbers to 1 string number_str = str_number(T) Next For G As Integer = 0 To per_len ' set decimal numbers to another string percent_str = str_Percent(G) Next ' OK, now the strings are parsed and we can just convert each to a number and then add those numbers together Dim new_number As Double = Convert.
Input validation is a great place to begin learning about error handling and bug fixing.