Question

VISUAL BASIC-

create a program for managing a "To Do" list. The program will need to read and update a text file named ToDoList.txt. The record structure of the file must be: 1) sort order, 2) task name and 3) desired completion date.

When the program starts, it should read the contents file into a structure. The information should then be displayed in a data grid view. The data should be initially sorted by the sort order value. Afterwards, the user should be able to click on a column name to sort the data by that specific column.

The user should be able to add, update and delete tasks. The methods to implement these features are up to you. Please note that each value (sort order, task name and desired completion date) should be saved as a string value.

The program must use StreamReader and StreamWriter objects. The program must also contain exception handling for a missing input file. If the input file is not found, the user should be informed and still be allowed to use the program (i.e. do not automatically close the program).

Answer 1

Please read the visual basic code with comments for more explanation and do let me know in the comment box below if you face any errors, I will try my best to explain. Here clicking on update button will write the data to file. Add button will add a blank row to the data grid view for new entry (duble click on the cell to edit the details). Delete button will remove the selected row and then click on update button to save the changes before exiting the application.

Output:

ToDo List Sort Order Task Name Breath Drink Water Desired_Completior 21-04-2017 22-04-2017 Add Update

Text File: (comma separated for better readability)

ToDoList - Notepad File Edit Format View Help 1,Breath, 21-04-2017, 2,Drink water,22-04-2017,

Visual Basic Code:

Imports System.IO 'import for file reading operations

Public Class Form

Private Sub Form_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Try
Using fileReader As StreamReader = New StreamReader("D:\ToDoList.txt") 'provide correct file path here
Dim fileLine As String = ""
Dim index As Integer = 0
Dim temp(3) As String 'A temp array to store each row at a time (3 columns)
fileLine = fileReader.ReadLine()
While (fileLine <> Nothing) 'read file until the end of the file
temp = fileLine.Split(CChar(",")) 'split the file line with ',' delimeter
'temp(0) contains Sorting Order, temp(1) contains Task Name, temp(2) contains Desired Date
DataGridView.Rows.Add(temp(0), temp(1), temp(2))
fileLine = fileReader.ReadLine()
End While
End Using

Catch err As Exception
'let the user know if any error/exception occurs
MessageBox.Show("Error: " + err.Message)
End Try
End Sub

Private Sub saveList()
Try
Using fileWriter As StreamWriter = New StreamWriter("D:\ToDoList.txt") 'provide correct file path here
For i As Integer = 0 To DataGridView.Rows.Count - 1 Step +1
For j As Integer = 0 To DataGridView.Columns.Count - 1 Step +1
fileWriter.Write(DataGridView.Rows(i).Cells(j).Value.ToString + ",")
Next
fileWriter.WriteLine()
Next
fileWriter.Close()
End Using

Catch err As Exception
'let the user know if any error/exception occurs
MessageBox.Show("Error: " + err.Message)
End Try
End Sub

Private Sub addButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles addButton.Click
DataGridView.Rows.Add("", "", "")

End Sub

Private Sub deleteButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles deleteButton.Click
Dim RowIndex As Integer
For i As Integer = 0 To DataGridView.SelectedCells.Count - 1
RowIndex = DataGridView.SelectedCells.Item(i).RowIndex
Next

If RowIndex < 0 Then 'if row selected then alert the user
MsgBox("Please select any row to delete !")
Else
DataGridView.Rows.RemoveAt(RowIndex)
MsgBox("Selected row has been deleted !")
End If
End Sub

Private Sub updateButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles updateButton.Click
'save the rows to file if update button is clicked
saveList()
MsgBox("Data saved to file successfully.")
End Sub
End Class