How to create an Update button for a database? - vb.net

Question

I have a problem concerning my Update button, I don't know where to start to make it update my SQL database, I use SSMS Microsoft to create my table Subjects and I also connected it with my VS 2010 ULTIMATE where I drag my table to LINQtoSQL and DATASET, I have created a Save button which successfully saves to my database and refreshes my datagridview.
[ Private Sub Button18_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
If txtSubjectName.Text = "" Then
ErrorProvider1.SetError(txtSubjectName, "Subject Name Cannot be Empty!")
Exit Sub
ElseIf txtSubSName.Text = "" Then
ErrorProvider2.SetError(txtSubSName, "Subject Short Name Cannot be Empty!")
Exit Sub
End If
Dim db As New EMSDataContext
Dim SaveSubject = From C In db.Subjects
Where C.SubjectName = txtSubjectName.Text
Select C
If SaveSubject.Count <> 0 Then
MsgBox("Subject already exits!!", MsgBoxStyle.Exclamation + MsgBoxStyle.OkOnly, "Alart!!")
Exit Sub
Else
Dim SaveNSubject As New Subject With {.SubjectName = txtSubjectName.Text, .ShortName = txtSubSName.Text}
db.Subjects.InsertOnSubmit(SaveNSubject)
db.SubmitChanges()
MsgBox("Subject added successfully!", MsgBoxStyle.Information + MsgBoxStyle.OkOnly, "Information")
End If
Registration_Load(sender, e)
txtSubjectName.Text = ""
txtSubSName.Text = ""
End Sub]
And I also have a Delete button which successfully deletes my data from database and refreshes my datagridview.
[Private Sub Button13_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDelete.Click
Dim A As New EMSDataContext
Dim B = From C In A.Subjects
Where C.ID = Val(DtgvSubject.CurrentRow.Cells(0).Value)
Select C
Try
A.Subjects.DeleteOnSubmit(B.FirstOrDefault)
If MsgBox("Are You Sure to Delete This Record?", MsgBoxStyle.Question + vbYesNo, "Question") = MsgBoxResult.Yes Then
A.SubmitChanges()
MsgBox("Record Deleted Successfully!", MsgBoxStyle.Information + MsgBoxStyle.OkOnly, "Information")
txtSubjectName.Text = ""
txtSubSName.Text = ""
Registration_Load(sender, e)
Else
txtSubjectName.Text = ""
txtSubSName.Text = ""
Registration_Load(sender, e)
End If
Catch ex As Exception
MsgBox("Select a Record First!", MsgBoxStyle.Exclamation + MsgBoxStyle.OkOnly, "ALERT!!!")
End Try
If B.Count = 0 Then
MsgBox("Please select list to delete!", MsgBoxStyle.Exclamation + MsgBoxStyle.OkOnly, "Alart!!")
End If
End Sub]
I also created a double click Events of the datagridview cell where I get cells values to my Subject Name textbox and Subject Short Name textbox if I double clicked which is also successfull.
[ Private Sub DtgvSubject_CellDoubleClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DtgvSubject.CellDoubleClick
Try
Dim i As Integer
i = DtgvSubject.CurrentRow.Index
Me.txtSubjectName.Text = DtgvSubject.Item(1, i).Value
Me.txtSubSName.Text = DtgvSubject.Item(2, i).Value
Catch ex As Exception
MsgBox("No Values in the Cells!", MsgBoxStyle.Exclamation + MsgBoxStyle.OkOnly, "Alert!!!")
Button17_Click(sender, e)
End Try
End Sub]
My Question is, how can I create an Update button to my Database after getting the Values to the Textboxes and update them, Submit Changes and refresh my datagridview?

Answer 1

Assuming your inputs are not bound to the dataset, you just need to retrieve the existing record from the database, update the record and save it again. Something like this should work:
public Function updaterecord (field1 as integer, field2 as text) as Object
Dim db As New EMSDataContext
Dim SaveSubject = From C In db.Subjects
Where C.SubjectName = txtSubjectName.Text
Select C
if SaveSubject is not Nothing then
C.id = field1
C.name = field2 'etc etc
End if
db.SaveChanges()
return
From C In db.Subjects
Where C.SubjectName = txtSubjectName.Text
Select C
End Function

Answer 2

Thank you Haim i have solved the Problem using LinqtoSQL
[ Private Sub bnUpdate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnUpdate.Click
If txtClassTeacher.Text = "" Or txtClassName.Text = "" Or txtClassSName.Text = "" Or cboClassSection.Text = "" Then
MsgBox("Select the data you want Update Please!", MsgBoxStyle.Exclamation + MsgBoxStyle.OkOnly, "ALERT!!!")
Exit Sub
End If
Dim db As New EMSDataContext
Dim SaveClasses = From c In db.Classtbls
Where c.ID = Val(DtgvClasstbl.CurrentRow.Cells(0).Value)
Select c
For Each c As Classtbl In SaveClasses
c.Class_Teacher = txtClassTeacher.Text
c.Class_Name = txtClassName.Text
c.Short_Name = txtClassSName.Text
c.Section = cboClassSection.Text
'Inserting additional changes
Next
'Submitting changes to the Database
Try
If MsgBox("Are You Sure You Want Update This Record?", MsgBoxStyle.Question + vbYesNo, "Question") = MsgBoxResult.Yes Then
db.SubmitChanges()
MsgBox("Data Successfully Updated!", MsgBoxStyle.Information + MsgBoxStyle.OkOnly, "Success!")
Registration_Load(sender, e)
txtClassTeacher.Text = ""
txtClassName.Text = ""
txtClassSName.Text = ""
cboClassSection.Text = ""
Else
Registration_Load(sender, e)
txtClassTeacher.Text = ""
txtClassName.Text = ""
txtClassSName.Text = ""
cboClassSection.Text = ""
End If
Catch ex As Exception
MsgBox("Update not Successful!", MsgBoxStyle.Exclamation + MsgBoxStyle.OkOnly, "ALERT!!!")
'Making(Adudjstiment)
db.SubmitChanges()
End Try
End Sub]
Thank you StackOverflow and MSDN for guidance