We Keep Coding

using a try catch statement to keep a text box cleared

I am making a windows form application that takes various game entries (title,genre,price) and then stores them in an array with a maximum of four entries.
The error I am having is that if there are no values entered in my text boxes, I want a message box to appear to force the user to enter values. This happens.
The problem is that after this, it does not give the user another try. It just stops the program. I have tried using a try catch statement to do this but I am not quite sure how to use this. Would this be the correct solution?
namespace gameForm
{
public partial class gameEntryForm : Form
{
public gameEntryForm()
{
InitializeComponent();
}
struct Game
{
public string Title;
public string Genre;
public decimal Price;
}
static Game[] aNewGame = new Game[4]; //max size of the array is 4
static int newGameEntryIndex = 1;
private void gameEntryForm_Load(object sender, EventArgs e)
{
aNewGame[0].Title = "golf tour"; //this is a game already stored in the database
aNewGame[0].Genre = "sports";
aNewGame[0].Price = 1.99m;
}
private void btnSave_Click(object sender, EventArgs e)
{
try
{
if (String.IsNullOrEmpty(tbGenre.Text))
{
MessageBox.Show("please enter a Game genre.");
}
if (String.IsNullOrEmpty(tbTitle.Text))
{
MessageBox.Show("please enter a Game title");
}
if (String.IsNullOrEmpty(tbPrice.Text))
{
MessageBox.Show("please enter a Game price");
}
}
//catch()
//{
//}
aNewGame[newGameEntryIndex].Title = tbTitle.Text;
aNewGame[newGameEntryIndex].Genre = tbGenre.Text;
aNewGame[newGameEntryIndex].Price = Convert.ToDecimal(tbPrice.Text);
newGameEntryIndex++;
MessageBox.Show("entry saved");
//clears the text boxes
tbTitle.Clear();
tbGenre.Clear();
tbPrice.Clear();
}
private void btnShow_Click(object sender, EventArgs e)
{
rtbShow.Text = "Game Details \n\nGame 1 \n" + aNewGame[0].Title + "\n" + aNewGame[0].Genre + "\n" + aNewGame[0].Price + "\n\n" + "Game 2 \n" + aNewGame[1].Title + "\n" + aNewGame[1].Genre + "\n" + aNewGame[1].Price + "\n\n" + "Game 3 \n" + aNewGame[2].Title + "\n" + aNewGame[2].Genre + "\n" + aNewGame[2].Price + "\n\n" + "Game 4 \n" + aNewGame[3].Title + "\n" + aNewGame[3].Genre + "\n" + aNewGame[3].Price; ;
}
//clears the rich text box
private void btnClear_Click(object sender, EventArgs e)
{
rtbShow.Clear();
}
private void btnQuit_Click(object sender, EventArgs e)
{
Application.Exit();
}
}
}

Add a return, no try/catch required:
if (String.IsNullOrEmpty(tbGenre.Text))
{
MessageBox.Show("please enter a Game genre.");
return; // Exit current function
}
Try/catch is for when you have exceptions.

Try-Catch is of no use to you.
What you should do is in the btnSave_Click method return when the textboxes are not populated:
if (String.IsNullOrWhiteSpace(tbGenre.Text) ||
String.IsNullOrWhiteSpace(tbTitle.Text) ||
String.IsNullOrWhiteSpace(tbPrice.Text)
{
MessageBox.Show("Please enter a game genre, game title and game price.");
return;
}
aNewGame[newGameEntryIndex].Title = tbTitle.Text;
...
There is another solution you could do. Only activate the Save-button if all three textboxes has values in them.
Something like:
private void ValidateGameData(object sender, EventArgs e)
{
if (String.IsNullOrWhiteSpace(tbGenre.Text) ||
String.IsNullOrWhiteSpace(tbTitle.Text) ||
String.IsNullOrWhiteSpace(tbPrice.Text))
{
btnSave.Enabled = false;
}
else
{
btnSave.Enabled = true;
}
}
tbGenre.TextChanged += ValidateGameData;
tbTitle.TextChanged += ValidateGameData;
tbPrice.TextChanged += ValidateGameData;

In your code for btnSave_Click you are testing the value of the various TextBoxes and displaying a message if they are NULL or empty.
However, you continue execution of your code even if they are NULL or empty.
You should stop processing more code if the conditions fail so that you don't try to use the NULL\empty values.
Something like:
private void btnSave_Click(object sender, EventArgs e)
{
if (String.IsNullOrEmpty(tbGenre.Text))
{
MessageBox.Show("please enter a Game genre.");
}
else if (String.IsNullOrEmpty(tbTitle.Text))
{
MessageBox.Show("please enter a Game title");
}
else if (String.IsNullOrEmpty(tbPrice.Text))
{
MessageBox.Show("please enter a Game price");
}
else
{
// You forgot to create the new game at this index
aNewGame[newGameEntryIndex] = new Game();
aNewGame[newGameEntryIndex].Title = tbTitle.Text;
aNewGame[newGameEntryIndex].Genre = tbGenre.Text;
aNewGame[newGameEntryIndex].Price = Convert.ToDecimal(tbPrice.Text);
newGameEntryIndex++;
MessageBox.Show("entry saved");
//clears the text boxes
tbTitle.Clear();
tbGenre.Clear();
tbPrice.Clear();
}
}
I've also added a line:
aNewGame[newGameEntryIndex] = new Game();
As I couldn't see anywhere that you created the new Game object before trying to set it's properties.

How to validate textbox value while user enters and display error message?

So, I have to code for a method that validates whether the string that saves name contains alphabets only, no numbers. The validation of textbox values should apply when the user enters by textchanged event before submitting the form and display an error message of red color on the label. My code works but the problem is when I enter a numeric number in text box, the label displays error which stays even when I delete the text box value and enter the alphabetic string.
I have declared a method which assign error string to label, and is called if regular expression does not match with the text box input, during text changed event.
public void Validator()
{
Calculate_Salary.Enabled = false;
label4.Text = "Please enter only alphabetical letters";
}
private void _Name_TextChanged(object sender, EventArgs e)
{
Regex pattern = new Regex("/^[A-Za-z]+$/");
string name = _Name.Text;
if (pattern.IsMatch(name))
{
Calculate_Salary.Enabled = true;
label4.Text = "";
}
else
{
Validator();
}
}

Just clear the textbox before you validate:
public void Validator()
{
Calculate_Salary.Enabled = false;
label4.Text = "Please enter only alphabetical letters";
}
private void _Name_TextChanged(object sender, EventArgs e)
{
label4.Text = "";
Regex pattern = new Regex("/^[A-Za-z]+$/");
string name = _Name.Text;
if (pattern.IsMatch(name))
{
Calculate_Salary.Enabled = true;
}
else
{
Validator();
}
}

Your Regex comparison is wrong try this code:
public void Validator()
{
Calculate_Salary.Enabled = false;
label4.Text = "Please enter only alphabetical letters";
}
private void _Name_TextChanged(object sender, EventArgs e)
{
label4.Text = "";
string name = _Name.Text;
if (Regex.IsMatch(name, #"^[a-zA-Z]+$"))
Calculate_Salary.Enabled = true;
else
Validator();
}

I changed the validation code. It seems to work now.
private void _Name_TextChanged(object sender, EventArgs e)
{
label4.Text = string.Empty;
string name = _Name.Text;
if (Regex.IsMatch(_Name.Text, "^[a-zA-Z]+$") || _Name.Text=="")
{
Calculate_Salary.Enabled = true;
}
else
{
Calculate_Salary.Enabled = false;
label4.Text = Validator();
}
}

Delete Button not deleting items in ListBox

Through the answers and help on a previous question. I have now come across another issue.
My btnDelete_MouseClick() event is not deleting the customer information that is stored in the textBox's.
I want it to take in the info like: Ashton Smith 864123456789
And then when the exact same info is in the corresponding textFields and I hit the delete button it removes it from the listBox.
This is what I have so far. It runs but it does not delete the customer from the listBox.
public partial class Form1 : Form
{
Customer cust;
public Form1()
{
InitializeComponent();
tbxFirstName.CharacterCasing = CharacterCasing.Upper;
tbxFirstName.MaxLength = 35;
tbxLastName.CharacterCasing = CharacterCasing.Upper;
tbxLastName.MaxLength = 35;
tbxPhone.MaxLength = 10;
listBoxDatabase.Name = "CUSTOMERS";
}
private void btnAddCustomer_MouseClick(object sender, MouseEventArgs e)
{
//string customer = tbxFirstName.Text + " " + tbxLastName.Text + " " + tbxPhone.Text;
cust = new Customer(tbxFirstName.Text, tbxLastName.Text, tbxPhone.Text);
if (listBoxDatabase.Items.Cast<Customer>().Any(x => x.ToString() == cust.ToString()))
{
MessageBox.Show("Customer Already Exist!", "ERROR");
}
else
{
listBoxDatabase.Items.Add(cust);
}
}
private void btnDelete_MouseClick(object sender, MouseEventArgs e)
{
Customer custToDelete = listBoxDatabase.Items.Cast<Customer>().FirstOrDefault(x => x.ToString() == cust.ToString());
if (custToDelete != null)
{
listBoxDatabase.Items.Remove(cust);
}
else
{
MessageBox.Show("No Customer Found!", "ERROR");
}
}
private void listBoxDatabase_SelectedIndexChanged(object sender, EventArgs e)
{
if (listBoxDatabase.SelectedIndex != -1)
{
Customer cust = listBoxDatabase.Items[listBoxDatabase.SelectedIndex] as Customer;
tbxFirstName.Text = cust.getFirstName;
tbxLastName.Text = cust.getLastName;
tbxPhone.Text = cust.getPhone;
}
}
}

You logic for deletion is wrong. You should not use .ToString() to compare objects. You can Cast the Selected Item of the ListBox to your specific type and then Remove that from the items collection:
Customer selected = listBoxDatabase.SelectedItem as Customer;
if(selected != null)
listBoxDatabase.Items.Remove(selected);
else
MessageBox.Show("No Customer Found!", "ERROR");

How do you add items to a listbox on a second form?

Working on a project for school that has 2 forms. I want to add items to the listbox in the Display form when I click the show data button. It's showing the form but the form is blank. I think this is because the form object is being created 2x once when I click the add button and another when I click the show data button. How can I create a new object of the display form that can be used in any method in my main form?
Sorry there is a few things in here that I am still working on that were just ideas. I am a beginner so please keep the help in simple terms if at all possible. Thanks :)
private void addEmployee(Employee newEmployee)
{
//Get data from textboxes and use set methods in employee class
newEmployee.Name = EmployeeNameTextBox.Text;
newEmployee.BirthDate = EmployeeBirthDateTextBox.Text;
newEmployee.Dept = EmployeeDeptTextBox.Text;
newEmployee.HireDate = EmployeeHireDateTextBox.Text;
newEmployee.Salary = EmployeeSalaryTextBox.Text;
}
private void AddButton_Click(object sender, EventArgs e)
{
//New list for employee class objects - employeelist
List<Employee> employeeList = new List<Employee>();
//Create new instance of Employee class - newEmployee
Employee newEmployee = new Employee();
bool errorCheck = false;
CheckForms(ref errorCheck);
if (!errorCheck)
{
//Gather input from text boxes and pass newEmployee object
addEmployee(newEmployee);
//Add object to employeeList
employeeList.Add(newEmployee);
Display myDisplay = new Display();
myDisplay.OutputListBox.Items.Add(" Bob");
//" " + newEmployee.BirthDate + " " +
//newEmployee.Dept + " " + newEmployee.HireDate + " " + newEmployee.Salary);

You are creating two separate instances of mydisplay.Create a single instance when the Form Loads and refer to that when you call ShowDataButton_Click
namespace WK4
{
public partial class MainForm : Form
{
Display myDisplay;
public MainForm()
{
InitializeComponent();
}
//Method to clear form input boxes
private void ClearForm()
{
EmployeeNameTextBox.Text = "";
EmployeeBirthDateTextBox.Text = "";
EmployeeDeptTextBox.Text = "";
EmployeeHireDateTextBox.Text = "";
EmployeeSalaryTextBox.Text = "";
FooterLabel.Text = "";
}
//Method to check for blank input on textboxes
private void CheckForms(ref bool error)
{
if (EmployeeNameTextBox.Text == "" || EmployeeBirthDateTextBox.Text == "")
{
MessageBox.Show("Please do not leave any fields blank");
error = true;
}
else if (EmployeeDeptTextBox.Text == "" || EmployeeHireDateTextBox.Text == "")
{
MessageBox.Show("Please do not leave any fields blank");
error = true;
}
else if (EmployeeSalaryTextBox.Text == "")
{
MessageBox.Show("Please do not leave any fields blank");
error = true;
}
else
error = false;
}
private void addEmployee(Employee newEmployee)
{
//Get data from textboxes and use set methods in employee class
newEmployee.Name = EmployeeNameTextBox.Text;
newEmployee.BirthDate = EmployeeBirthDateTextBox.Text;
newEmployee.Dept = EmployeeDeptTextBox.Text;
newEmployee.HireDate = EmployeeHireDateTextBox.Text;
newEmployee.Salary = EmployeeSalaryTextBox.Text;
}
private void AddButton_Click(object sender, EventArgs e)
{
//New list for employee class objects - employeelist
List<Employee> employeeList = new List<Employee>();
//Create new instance of Employee class - newEmployee
Employee newEmployee = new Employee();
bool errorCheck = false;
CheckForms(ref errorCheck);
if (!errorCheck)
{
//Gather input from text boxes and pass newEmployee object
addEmployee(newEmployee);
//Add object to employeeList
employeeList.Add(newEmployee);
Display myDisplay = new Display();
myDisplay.OutputListBox.Items.Add(" Bob");
//" " + newEmployee.BirthDate + " " +
//newEmployee.Dept + " " + newEmployee.HireDate + " " + newEmployee.Salary);
//Clear Form after adding data
ClearForm();
//Print footer employee saved info
FooterLabel.Text = ("Employee " + newEmployee.Name + " saved.");
}
}
//Exit the form/program
private void ExitButton_Click(object sender, EventArgs e)
{
this.Close();
}
//Method to clear the form and reset focus
private void ClearButton_Click(object sender, EventArgs e)
{
ClearForm();
EmployeeNameTextBox.Focus();
}
private void ShowDataButton_Click(object sender, EventArgs e)
{
myDisplay.ShowDialog();
}
private void MainForm_Load(object sender, EventArgs e)
{
myDisplay = new Display();
}
}
}

You are making 2 different instances of display class, in first instance you are adding data and you are displaying it using the second instance thats why you are getting a blank form
create a display class object on your MainForm_Load
private void MainForm_Load(object sender, EventArgs e)
{
Display myDisplay = new Display();
}
and the use this object (myDisplay) to add and display data in your AddButton_Click and ShowDataButton_Click methods respectively.

How to check in real time if data was enteder from one of the classes into a texbox?

My question comes from a problem which I have right now. I have MainWindow, AuthenticateWindow, and AddEntryWindow which all are WinForms. In main window I have possibility to Authenticate and Add Entry into my main windows textbox. They can not add an entry until they authenticate (no problem with this). I need to add an entry to the text box which will update my main windows textbox. The problem if, how can I check if entry was added to my textbox?
I am trying to have a Save option from menu strip. I am getting an error whenever I am trying to save an empty file. How could I authenticate the saving process by Save button by having it first disabled, and enabled after entry was added?
I could always verify if if textbox had an entry but I want to have button disabled first, and enabled after entry was added. I do not have a privilege to do so as of right now.
Please ask questions if I am not clear enough.
private void tsmiSave_Click(object sender, EventArgs e)
{
// Open sfdSaveToLocation which let us choose the
// location where we want to save the file.
if (txtDisplay.Text != string.Empty)
{
sfdSaveToLocation.ShowDialog();
}
}
MainWindow.cs
using System;
using System.IO;
using System.Windows.Forms;
namespace Store_Passwords_and_Serial_Codes
{
public partial class MainWindow : Form
{
private AuthenticateUser storedAuth;
public MainWindow()
{
InitializeComponent();
}
private void MainWindow_Load(object sender, EventArgs e)
{
// Prohibit editing.
txtDisplay.Enabled = false;
}
public string ChangeTextBox
{
get
{
return this.txtDisplay.Text;
}
set
{
this.txtDisplay.Text = value;
}
}
private void tsmiAuthenticate_Click(object sender, EventArgs e)
{
AuthenticationWindow authWindow = new AuthenticationWindow();
authWindow.ShowDialog();
storedAuth = authWindow.Result;
}
private void tsmiAddEntry_Click(object sender, EventArgs e)
{
if (storedAuth == null)
{
DialogResult result = MessageBox.Show
("You must log in before you add an entry."
+ Environment.NewLine + "You want to authenticate?",
"Information", MessageBoxButtons.YesNo,
MessageBoxIcon.Information);
if (result == DialogResult.Yes)
{
AuthenticationWindow authWindow =
new AuthenticationWindow();
authWindow.ShowDialog();
storedAuth = authWindow.Result;
AddEntryWindow addWindow = new AddEntryWindow
(this, storedAuth.UserName, storedAuth.Password);
addWindow.ShowDialog();
}
}
else
{
AddEntryWindow addWindow = new AddEntryWindow
(this, storedAuth.UserName, storedAuth.Password);
addWindow.ShowDialog();
}
}
private void tsmiClose_Click(object sender, EventArgs e)
{
this.Close();
}
private void tsmiSave_Click(object sender, EventArgs e)
{
// Open sfdSaveToLocation which let us choose the
// location where we want to save the file.
sfdSaveToLocation.ShowDialog();
}
private void sfdSaveToLocation_FileOk(object sender, System.ComponentModel.CancelEventArgs e)
{
string theFileName = sfdSaveToLocation.FileName;
EncryptDecrypt en = new EncryptDecrypt();
string encrypted = en.Encrypt(txtDisplay.Text,
storedAuth.UserName, storedAuth.Password);
MessageBox.Show(encrypted);
File.WriteAllText(theFileName, encrypted);
}
}
}
AddEntryWindow.cs
using System;
using System.Windows.Forms;
// Needed to be used with StringBuilder
using System.Text;
// Needed to be used with ArrayList.
using System.Collections;
namespace Store_Passwords_and_Serial_Codes
{
public partial class AddEntryWindow : Form
{
string user, pass;
// Initializind ArrayList to store all data needed to be added or retrived.
private ArrayList addedEntry = new ArrayList();
// Initializing MainWindow form.
MainWindow mainWindow;
// Default constructor to initialize the form.
public AddEntryWindow()
{
InitializeComponent();
}
public AddEntryWindow(MainWindow viaParameter, string user, string pass)
: this()
{
mainWindow = viaParameter;
this.user = user;
this.pass = pass;
}
private void AddEntryWindow_Load(object sender, EventArgs e)
{ }
private void btnAddEntry_Click(object sender, EventArgs e)
{
// Making sure that type is selected.
if (cmbType.SelectedIndex == -1)
{
MessageBox.Show("Please select entry type!", "Error!",
MessageBoxButtons.OK, MessageBoxIcon.Error);
}
// Each field must be filled for specified type.
// Here we are checking if all fields were filled.
else if ((cmbType.SelectedIndex == 0 && (txtUserName.Text == string.Empty || txtPassword.Text == string.Empty)) ||
(cmbType.SelectedIndex == 1 && (txtURL.Text == string.Empty || txtPassword.Text == string.Empty)) ||
(cmbType.SelectedIndex == 2 && (txtSoftwareName.Text == string.Empty || txtSerialCode.Text == string.Empty)))
{
MessageBox.Show("Please fill all the fields!", "Error!",
MessageBoxButtons.OK, MessageBoxIcon.Error);
}
else
{
int totalEntries = 0;
if(cmbType.SelectedIndex == 0)
addedEntry.Add(new AddPC(cmbType.Text,
txtUserName.Text, txtPassword.Text));
else if(cmbType.SelectedIndex == 1)
addedEntry.Add(new AddWebSite(cmbType.Text,
txtUserName.Text, txtPassword.Text, txtURL.Text));
else if(cmbType.SelectedIndex == 2)
addedEntry.Add(new AddSerialCode(cmbType.Text,
txtSoftwareName.Text, txtSerialCode.Text));
StringBuilder stringBuilder = new StringBuilder();
foreach (var list in addedEntry)
{
if (list is AddPC)
{
totalEntries++;
AddPC tmp = (AddPC)list;
stringBuilder.Append(tmp.ToString());
}
else if (list is AddWebSite)
{
totalEntries++;
AddWebSite tmp = (AddWebSite)list;
stringBuilder.Append(tmp.ToString());
}
else if (list is AddSerialCode)
{
totalEntries++;
AddSerialCode tmp = (AddSerialCode)list;
stringBuilder.Append(tmp.ToString());
}
}
mainWindow.ChangeTextBox = stringBuilder.ToString();
mainWindow.tsslStatus.Text = "A total of " + totalEntries + " entries added.";
// Clearing all fields.
ClearFields();
}
}
private void btnClear_Click(object sender, EventArgs e)
{
ClearFields();
}
private void btnClose_Click(object sender, EventArgs e)
{
// Closing the Add Entry Window form.
this.Close();
}
private void cmbType_SelectedIndexChanged(object sender, EventArgs e)
{
// Deciding which data must be entered depending on
// what type is selected from combo box.
// PC
if (cmbType.SelectedIndex == 0)
{}
// Web Site
else if (cmbType.SelectedIndex == 1)
{}
// Serial Code
else if (cmbType.SelectedIndex == 2)
{}
}
private void ClearFields()
{
// Clearing all fields to the default state.
}
}
}
Regards.

It sounds like you probably just want to subscribe to the TextChanged event, which will be fired whenever the text in the textbox changes.
I can't say I really followed everything that you're doing, but I think you should be fine to just enable or disable your Save button within that event handler.
EDIT: It's not really clear where all your different components live, but you want something like:
// Put this after the InitializeComponent() call in the constructor.
txtDisplay.TextChanged += HandleTextBoxTextChanged;
...
private void HandleTextBoxTextChanged(object sender, EventArgs e)
{
bool gotText = txtDisplay.Text.Length > 0;
menuSaveButton.Enabled = gotText;
}
I'd also strongly advise you not to use ArrayList but to use the generic List<T> type. The non-generic collections should almost never be used in new code.