如何从Visual Basic 2013 .net中的DataGridView更新SQLite数据库？

Question

I am displaying data from SQLite table into a DataGridView as following -

Private Sub Subjects_Manager_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        con = New SQLiteConnection("Data Source = c:\demo\test.db;Version=3;")
        con.Open()
        sql = "SELECT * FROM med_subjects"
        da = New SQLiteDataAdapter(sql, con)
        da.Fill(ds, "SubjectsList")
        DataGridView1.DataSource = ds.Tables("SubjectsList").DefaultView
        With DataGridView1
            .RowHeadersVisible = False
            .Columns(0).HeaderCell.Value = "Subject Id"
            .Columns(1).HeaderCell.Value = "Subject Name"
        End With
        DataGridView1.Sort(DataGridView1.Columns(0), System.ComponentModel.ListSortDirection.Ascending)
        con.close()
End Sub

I want to save changes done in DataGridView (either Updation of Row/s or Insertion of Row/s) back to SQLite table . But I couldn't find a way to do so.

Edit 1 : I know Insert/Update Queries of SQLite, but what I don't know is how & where to keep them so that they can be triggered in responses to changes made in DataGridView. eg

' I am using this variable for demonstration, in reality InsertSubjectSqlString will be equal to changes done in DataGridView

Dim InsertSubjectSqlString As String = "Insert into med_subjects (Subject_Name) Values ('_Miscellaneous')"
Dim SqliteInsertRow As SQLiteCommand
SqliteInsertRow = con.CreateCommand
SqliteInsertRow.CommandText = InsertSubjectSqlString
SqliteInsertRow.ExecuteNonQuery()

But I don't know, where should I put it?

Edit 2: After seeing comments and answers, I came to know that there is No direct way to Insert/Update Sqlite database from DataGridView. So I was curious, if there is any event like RowSelected which would

• trigger on selecting a row and get that row's data
• then taking the row's data into multiple text boxes and lastly
• triggering Insert/Update queries taking values from these textboxes by a button

I know it's highly hypothetical with NO sample codes, but it's because I am asking for Event name.

Answer 1

Call this on LeaveRow event or CellEndEdit

  Private Sub DataGridView1_RowLeave(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.RowLeave
 Dim i as integer
 Try
 for i = 0 to datagrid.rows.count-1
      myUpdate(datagrid.item(0,i).tostring() , datagrid.item(1,i).tostring())
 next
 Catch ex As Exception
 MsgBox(Err.Description)
 End Try
 End Sub

note , you can also give the column name of your grid in place of column index , like this datagrid.item("fname",i).tostring()

Here we will save in database:

  Sub myUpdate(byval fname as string , byval lname as string)
Try
 dim con as new sqlconnection("you connection string")
 dim cmd as new sqlcommand
      con.open()
      cmd.connection= con
      cmd.commandtext="insert into table (fname,lname) values (@fname,@lname)"
      cmd.Parameters.AddWithValue("@fname", fname)
      cmd.Parameters.AddWithValue("@lname", lname)
      cmd.ExecuteNonQuery()
      Con.close()
      Catch ex As Exception
      MsgBox(Err.Description)
      End Try
 End sub

I hope this will help you to solve !
There are many ways to manipulate data .
CristiC

Answer 2

I dont think you will find some magic way that the DataGridView and DataTable are going to persist things automatically to the backend SQLite database. As you are hinting at I think you will have to rely on events.

I think the event you are missing is answered here stackoverflow cell value changed event

Answer 3

Ok I think is better to use CellEndEdit, because LeaveRow is triggered only if you click on other row.
Look on this example.
you must
use: da.Update(ds.Tables("SubjectsList").DefaultView)

 Imports System.Data.SqlClient

Public Class Form1

Const connectionstring As String = "server=(local);database=TestDB;uid=sa;pwd=sa;"
Private SQL As String = "select * from customer"
Private con As New SqlConnection(connectionstring)
Private dt As New DataTable
Private adapter As New SqlDataAdapter(SQL, con)
Private commandbuilder As New SqlCommandBuilder(adapter)

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    adapter.Fill(dt)
    DataGridView1.DataSource = dt
End Sub

Private Sub DataGridView1_RowLeave(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.RowLeave
    adapter.Update(dt)
End Sub

End Class

Answer 4

Please use this code hopefully it will work

Imports System.Data.SQLite

Public Class Form       
Dim con As New SQLite.SQLiteConnection
        Dim da As New SQLite.SQLiteDataAdapter
        Dim dt As New DataTable
        Dim cmdbl As New SQLite.SQLiteCommandBuilder
        Dim dlgResult As DialogResult     

        Private Sub btnUpdate_Click(sender As Object, e As EventArgs) Handles btnUpdate.Click
             dlgResult = MessageBox.Show("Do you want to save the changes you made?", "Confirmation!", MessageBoxButtons.YesNo)
                            If dlgResult = DialogResult.Yes Then
                                Try
                                    con.Open()
                                    cmdbl = New SQLiteCommandBuilder(da)

                                    da.Update(dt)
                                    MsgBox("Updated successfully!")
                                    con.Close()
                                Catch ex As Exception
                                    MsgBox(ex.ToString)
                                End Try

                            End If
    End Sub
End Class