In my last tutorial I teach you how to save multiple data in MySQL database. This time, I will teach you how to delete multiple data with a selector which is a CheckBox. With this, you can choose whatever data you want to delete and it is very useful.

Now lets begin:

I already created the MySQL Database in my first tutorial. Just click here.

1. Open the Visual Basic 2008.
2. Create a Project.
3. Set your Form just like this.



Double click the Form and do this code above the Form_load

.
This code is for setting up the connection of MySQL Database and declaring all the variables and classes that you needed.

1. 'set your imports
   
2. Imports
   
   MySql.
   
   Data
   
   .
   
   MySqlClient
   
3. Public
   
   Class
   
   Form1
   
4. 'set up your connection of MySQL database
   
5. Dim
   
   con As
   
   MySqlConnection =
   
   New
   
   MySqlConnection(
   
   "server=localhost;user id=root;database=test"
   
   )
   
6. 'a set of COMMANDS in MySQL
   
7. Dim
   
   cmd As
   
   New
   
   MySqlCommand
   
8. 'a bridge between the database and the datatable for saving and retrieving data
   
9. Dim
   
   da As
   
   New
   
   MySqlDataAdapter
   
10. 'a specfic table in the database
    
11. Dim
    
    dt As
    
    New
    
    DataTable
    
12. 'variable string for storing value
    
13. Dim
    
    sql As
    
    String
    
14. 'variable integer for storing value
    
15. Dim
    
    result As
    
    Integer
    
16. End
    
    Class
    

After that, create a Sub procedure for retrieving data in MySQL Database. So that, you can call the SubName and put it in different places that you want.

1. 'a Sub Procedure for retrieving data
   
2. Public
   
   Sub
   
   listrecords(
   
   )
   
3. Try
   
4. 'opening the connection
   
5. con.
   
   Open
   
   (
   
   )
   
6. 'store your select query to a variable(sql)
   
7. sql =
   
   "SELECT * FROM member"
   
8. 'set a new specific table in the database
   
9. dt =
   
   New
   
   DataTable
   
10. 'Set your MySQL COMMANDS
    
11. With
    
    cmd
    
12. .
    
    Connection
    
    =
    
    con
    
13. .
    
    CommandText
    
    =
    
    sql
    
14. End
    
    With
    
15. da =
    
    New
    
    MySqlDataAdapter(
    
    sql, con)
    
16. 'set the MySqlDataAdapter to add or refresh rows in a specified range in the dataset
    
17. 'to match those in the data source the data Table name.
    
18. da.
    
    Fill
    
    (
    
    dt)
    
19. 'to get or set the data source to diplay in the DataGridView
    
20. DataGridView1.
    
    DataSource
    
    =
    
    dt
    
21. Catch
    
    ex As
    
    Exception
    
22. MsgBox
    
    (
    
    ex.
    
    Message
    
    )
    
23. End
    
    Try
    
24. 'Releases all resources used by the MySqlDataAdapter
    
25. da.
    
    Dispose
    
    (
    
    )
    
26. 'close the connection
    
27. con.
    
    Close
    
    (
    
    )
    
28. End
    
    Sub
    

Under the Form_Load

, do the following codes for adding the CheckBox column and call the SubName for retrieving the data in MySQL Database.

1. Private
   
   Sub
   
   Form1_Load(
   
   ByVal
   
   sender As
   
   System.
   
   Object
   
   , ByVal
   
   e As
   
   System.
   
   EventArgs
   
   )
   
   Handles
   
   MyBase
   
   .
   
   Load
   
2. 'set a variable as a checkbox column in the DataGridView
   
3. Dim
   
   chkbox As
   
   New
   
   DataGridViewCheckBoxColumn
   
4. 'set the width of the column in the DataGridView
   
5. With
   
   chkbox
   
6. .
   
   Width
   
   =
   
   30
   
7. End
   
   With
   
8. 
   
9. With
   
   DataGridView1
   
10. 'Adding the checkbox column in the DataGridView
    
11. .
    
    Columns
    
    .
    
    Add
    
    (
    
    chkbox)
    
12. 'set the rows header to invisible
    
13. .
    
    RowHeadersVisible
    
    =
    
    False
    
14. End
    
    With
    
15. 'Put a Sub procedure name for Listing Records on the first load
    
16. listrecords(
    
    )
    
17. End
    
    Sub
    

Go back to the Design Views, double click the Delete Button. And under the Button1_Click

, do the following codes to delete the records in MySQL Database.

1. Private
   
   Sub
   
   Button1_Click(
   
   ByVal
   
   sender As
   
   System.
   
   Object
   
   , ByVal
   
   e As
   
   System.
   
   EventArgs
   
   )
   
   Handles
   
   Button1.
   
   Click
   
2. Try
   
3. 'opening the connection
   
4. con.
   
   Open
   
   (
   
   )
   
5. 'DataGridViewRow represents a row in the DataGridView Control
   
6. 'Rows is to get the collection of rows in the DataGridView control
   
7. 'the syntax is , getting the rows one by one
   
8. For
   
   Each
   
   row As
   
   DataGridViewRow In
   
   DataGridView1.
   
   Rows
   
9. 'Cells is to get the collection of cell that populate the row
   
10. 'FormattedValue is to get the value of the cell as formtted for display
    
11. 'the condition is, if the checkbox is checked then it delete the data in the database
    
12. If
    
    row.
    
    Cells
    
    (
    
    0
    
    )
    
    .
    
    FormattedValue
    
    =
    
    True
    
    Then
    
13. 'store your delete query to a variable(sql)
    
14. sql =
    
    "DELETE FROM member WHERE id = '"
    
    _
    
15. &
    
    CStr
    
    (
    
    row.
    
    Cells
    
    (
    
    1
    
    )
    
    .
    
    FormattedValue
    
    )
    
    &
    
    "'"
    
16. 'Set your MySQL COMMANDS
    
17. With
    
    cmd
    
18. .
    
    Connection
    
    =
    
    con
    
19. .
    
    CommandText
    
    =
    
    sql
    
20. End
    
    With
    
21. 'Execute the Data
    
22. result =
    
    cmd.
    
    ExecuteNonQuery
    
23. End
    
    If
    
24. Next
    
25. 'the condition is, if the result is equals to zero
    
26. 'then the message will appear and says "No Deleted Record."
    
27. 'and if not the message will appear and says "The Record(s) has been deleted."
    
28. If
    
    result =
    
    0
    
    Then
    
29. MsgBox
    
    (
    
    "No Deleted Record."
    
    )
    
30. Else
    
31. MsgBox
    
    (
    
    "The Record(s) has been deleted."
    
    )
    
32. End
    
    If
    
33. Catch
    
    ex As
    
    Exception
    
34. MsgBox
    
    (
    
    ex.
    
    Message
    
    )
    
35. End
    
    Try
    
36. 'Close the connection
    
37. con.
    
    Close
    
    (
    
    )
    
38. 'call the SubName for retrieving data to resfresh the list of Records in the DataGridView
    
39. listrecords(
    
    )
    
40. End
    
    Sub
    

Reminders: Read all the comments that I put , so that you will understand well what is happening and what are the functionalities in every code that I made.

You can download the complete Source Code and run it on your computer.

Download