Handle Errors Caused By Invalid User Input In A Program?
Mar 10, 2011
how do I handle the errors that may appear from the user of my program. For example, I have an triangle area program in wich I ask the user of the program to insert the length of the base and height of the triangle in a textbox. But what if he inserts a letter or something else, like a sign....my program will crash...
I know that one method would be to use On Error GoTo but I don't know how. If maybe you can direct me to some link or you could explain how do I handle errors, I would be grateful. Maybe you can even show me other ways to avoid errors from the user input.
This is my small program so far:
Private Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs)
Handles Button1.Click
Dim , Height, ARIA As Integer
[Code]....
View 3 Replies
ADVERTISEMENT
Nov 3, 2011
My console errors out when I enter anything other than a number or operators in the designated (input). I stink at this stuff but I have been t this for about 8 hrs. still not there. I have included a text file for the task at hand
[Code]...
View 1 Replies
Mar 20, 2011
I have several text boxes I need to validate. I am not understanding how to validate in Visual Basic 2008. So I deployed standard If Statements to handle bad data. I am having two problems.
Lets say the user entered wrong data, example, numbers; an error message is displayed. The text boxes cannot contain numbers, be left empty or contained characters, like !@#$. The problem is if the user enter text, and then entered a wrong data again the code does not work or display error message. How can I make the conditions so that they throw out error message even if the user had previously entered good data.
Another example: If the user enter good data in text box 1 and bad data in text box 2, the error message does not work.
Finally, how do I filter out characters to allow only text. Is there a way to use this code on multiple text boxes with out writing the entire code for each form control?
Here are the conditional statements.
Private Sub btnDataSubmit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDataSubmit.Click
If IsNumeric(txtDataEntry.Text) Then
lblErrorDisplay.Text = "Invalid Name!"
lblErrorDisplay.BackColor = Color.Red
[Code] .....
View 12 Replies
Jun 13, 2012
I'm trying to code a program that can download multiple files at once (on different threads of course).I have created a custom listview component that will allow me to add a progressbar directly to it.What my real question is, how can i take a url given by the user from an input box and create a new webclient to handle the download asynchronously and also report the progress without disturbing all of the other downloads in progress?
View 10 Replies
Apr 8, 2012
I have a procedure at the end of my console application that ask the user to either hit enter to end the program, or type s to perform another search. The issue I'm having is no matter what the user types in the program end. What I would like to happen is if the user types s, then the program starts over and lets the user perform another search. The program is procedural and I need to find a way to start back off at the top of the program which ask the user to type a name to search.
[Code]....
View 1 Replies
Mar 17, 2010
I'm tryng to figure out a way how I can stop my code from running while I wait for input from a device.Networked device that sends data to .net app.I now wish to prompt the user to answer a 'Continue' questoion and select either 'Yes' or 'No' on the device. This is transmitted to program over netstream.I want the code to pause though while waiting for an answer as different routines are run dependent on the answer.
View 5 Replies
Mar 10, 2010
I am making a vb.net program that calls several other subprograms. None of them effect the other.If there is an error in 1 of them, how do you record the error but continue on to the next subprogram with out stopping everything ?
View 1 Replies
Nov 23, 2009
I am using VB.Net code to print barcode label in Zebra TLP 2844 printer. And the printer is connected to system by USB port. When i execute the code i get an error "Invalid Parameter : Name handle" in the line outFile = New FileStream(_SafeFileHandle, FileAccess.Write) . As this is a USB port So i shared the printer and used the UNC path. But still i get the error. Below is the complete code
[Code]....
View 3 Replies
Jan 21, 2010
I am new to VB.Net and programming all together. I am trying to make a program that will take 2 numbers input by the user, Add them together and display the sum. Then take the sum and divide it individually by each number to give you what percent of the sum the numbers are. I'm working on making it a program that will calculate the Hardy-Weinberg equilibrium for my Anthro Class. I'm just doing this for practice for my VB.Net Class. But i will move onto that at a later time. I just want to finish this first.
So.. Here is my code so far. It's not complete yet but this is should be enough to make it function.
[Code]...
View 24 Replies
Jan 30, 2012
I am trying to write a program that allows user input information and plot a bifurcation diagram that looks like this:I haven't program in 2 years:sick: so I am all rusty and such. Here is what I have got so far and more information about what I am doing.
Bifurcation:
f(x) = kx(1-x)
and k = xL + i * (xR-xL) / 500
when i runs from 0 to 500, it plots (i, f(seed)), (i, f(f(seed)), .... up to the boundary number.Here is what I have got so far. Everything seems normal, however, I am really confused when it comes to plotting.
[Code]...
View 1 Replies
Dec 3, 2011
I recently installed Visual Studio 2010 which caused the same error, every time i try to start the program i get this message. i am using windows 7 professional 64bit i only have one user account, and i am the computer administartor. every other program works fine but visual studio programs.
View 2 Replies
Mar 12, 2011
how can I make an app that knows when it crashed and why.I had some thinking, and came up with the idea that I'll have a separate process, working in parallel with my app, and looking after it, and know when and why it had crashed.Can I make my app know when an imminent crash is coming and dump unsaved user data, not to be lost?Let's say that I have an app, that need's "GoRun.dll" to work, but it isn't there, so my app will crash, but can I make my app run long enough to download the "GoRun.dll" file from [URL]?(or have a parallel process to do it, started by the original process, that downloads the "GoRun.dll" file and restart my original app)
View 5 Replies
Mar 29, 2009
i want to make a program in which the user can input a mathematical function so the program can then work with it. So the user would input something like x^4+x+2 and then an x and the program would calculate f(x). What i don't know is how to let the user input the function.
View 6 Replies
Jan 2, 2012
I have a program written in VB 2010 express under windows xp which does some heavy number crunching combined with serial communication. When it "gets too busy" it does not update the screen anymore (done simply with Textbox.text = "any text") and it does not respond to user input in any text box. Not even to a click on any text box. Is there a way I can get the program to do screen update and respond to user input while it is busy?
View 3 Replies
Dec 3, 2009
I would like to create a form there I can enter three values (A,B,C)in textboxes and then submit these parameter to a program that run in a dos promt windows. Parameter A , B , C..Program.exe /A /B /C..It would be great if I can have a progress bar as well.
View 6 Replies
Oct 24, 2010
My project is GUI based. I want to write program in vb.net take some input from user and then i hav to genarate hex file so that it can be run on microcontroller. I just want to know weather hex file generation in vb.net is possible or not?
View 2 Replies
Oct 4, 2009
is it possible to add some VB.net code to handle all the errors in my application. (and not to go in each sub and add the on error intruction) I want to handle every error.
View 6 Replies
Jan 9, 2012
I am using Visual C# 2010 Express and Visual Basic 2010 Express on my Windows 8 developer preview PC.Before, there was no problem, both VB and C# work fine.But today, both VB and C# can't handle errors. I have created a simple application with VB and C#. (.Net framework 4.0) the codes are here:[code]But visual studio shows the dialog shown in first image instead of this dialog. So, I can't debug my program.If I enable break exception when thrown in Exceptions dialog, the problem solves, but at that point, visual studio breaks on EVERY exception , even handled exceptions... I don't want to break on every exception...
View 2 Replies
Dec 27, 2011
I have a relatively simple VB.NET app. It targets framework 2.0 from Visual Studio 2010. The app works fine most of the time, except that the users sometimes receive the
following exceptions. The error is completely random and somewhat rare. I haven't been able to trap it while in a development environment. It also doesn't appear to be
pointing at my code. My app continues to run if the users ignore the error. How would I trap and handle this error?
View 1 Replies
Dec 6, 2008
I'm currently developing a little hobby project to display health information in a game on my G15 keyboard through VB.NET. When I use ReadProcessMemory via an API call, it keeps returning zero. The MSDN documentation referred me to use the Marshal.GetLastWin32Error() call to find out what is wrong and it returns 1400: INVALID WINDOW HANDLE.
I am now confused about whether the first argument of the function wants a window handle or a process id. Regardless, I have tried both with FindWindow and hardcoding the process id while the application is running (getting it from task manager). I have tried three different games, Urban Terror, Grand Theft Auto: SA and 3D pinball for windows, getting the memory addresses from an application called Cheat Engine; they all seem to fail. [Code]
View 4 Replies
Jan 9, 2012
I know this idea of - if message boxes are used to display error messages inside a .dll and when the .dll is installed in a different computer (possibly a server machine), errors occurring inside that .dll will be shown in the server and not to the user. Since practically there will not be a person near the server to click 'OK' to the error message every time it occurs it will stuck the programs using the .dll.
So how to write exception handling to a .dll project?
View 1 Replies
Jul 18, 2010
In my VB.net Winforms application I'm using the ITaskbarList3::SetOverlayIcon interface to set status overlays on the application's taskbar button (under Windows 7). This all seems to work fine for me, with the icons being shown and removed correctly.From the form load event, one of my functions makes the callSetOverlayIcon(parentForm.Handle, IntPtr.Zero, String.Empty)(where parentForm is the form which the load event has fired for) which very occasionally (on other people's machines) throws the following exception:
System.Runtime.InteropServices.COMException (0x8007057A): Invalid cursor handle. (Exception from HRESULT: 0x8007057A)
at MyNamespace.TaskbarNotify.ITaskbarList3.SetOverlayIcon(IntPtr hwnd, IntPtr hIcon,
[code].....
View 1 Replies
Nov 2, 2011
Why does SetOverlayIcon throw an 'Invalid cursor handle' COMException occasionally
View 1 Replies
Apr 25, 2011
I'm trying to create a program, that upon opening, will read an input file containing a delimited employee record. The record will contain the name of the employee, their salary and the number of years they have been employed.I'm looking to display only the name of the employees in sorted order(alphabetically) and then when the user of the program selects a particular employee, I want to display the salary and number of years for that employee.I would like the user to be able to edit the recors for the employee and I would also like to have a way for the user to be able to add/remove an employee record and update the input file before the program is closed.
View 5 Replies
Oct 6, 2009
The local car rental company rents cars for 29.95 per day with unlimited mileage. There is a refueling fee of 12.95; regardless of what the level of fuel is when the car is returned. Write a program that will permit the user to input the customer's first and last names and the number of days that the car was rented. The program should compute the total charge for the car that was rented.
I have to do this:
A. using a standard window
B. Using a WPF window (And I don't even know what that means)
C. Using a console application
View 14 Replies
May 12, 2009
I'm currently in VB class at my highschool and we just got chapter 6.1 to read on this online textbook that we follow. Anyway, we are doing loops now and the problem reads "Write a program to request positive numbers one at a time from the user in an input dialog box. The user should be instructed to enter -1 after all the positive numbers have been supplied. At that time, the program should display the sum of the numbers." So far I know this much
[Code]...
Now I know this isn't right But I can't find out how I'd pull out the numbers the user entered to get the sum of them and not include -1 because as it stands, when I hit ENTER with -1 the label just shows -1.
View 22 Replies
Dec 6, 2010
I'm trying to read rows in a DataGridView and the following error is thrown up. The DataGridView was filled from an Excel Sheet with a column of currency. Ideally when the For Next loop finds a cell it doesn't like, I want to to ignore and resume the loop. The error message is: Object reference not set to an instance of an object
HTML
Try
For Each row As DataGridViewRow In Me.DataGridView2.Rows
FirstString = row.Cells(0).Value.ToString
[CODE]...
View 6 Replies
Jul 18, 2012
How can i check whether the text box is numeric or not? Because i want to do validation. but i tried many style still cannot work.
View 6 Replies
Dec 2, 2010
I am working on a program where a user either enters "small" or "large" and then the number of toppings. Once the user has done that my program outputs the total cost of a pizza based on user input. If they enter something else besides a number in the txtNumberOfToppings I am trying to show they message box that says "Re-Enter a valid number!" Likewise I am trying to display the error message "Re-enter a number that is 0 or greater!" If they enter a negative number into the textbox. However they do not display when I do enter invalid input.
My Code
Author: Adam Fandre
Description: User enters the words "SMALL" or "LARGE" and then the number of toppings
And program then displays cost based on user input.
Comments: Finished
Option Explicit On
Option Strict On
[Code] .....
View 6 Replies
Nov 23, 2009
Ok, I'm not sure how to explain this, but I'll give it my best shot.I want my console application to be able to do one function I have when you click one option on the windows context menu, and another function when you click another option.
View 2 Replies
