Question

我的“更新”按钮有问题，我不知道从哪里开始更新我的SQL数据库，我使用SSMS Microsoft创建我的表主题，我还将它与我的VS 2010 ULTIMATE连接在一起我将我的表拖到LINQtoSQL和DATASET，我创建了一个Save按钮，它成功保存到我的数据库并刷新我的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]

我还有一个删除按钮，可以成功从数据库中删除我的数据并刷新我的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]

我还创建了一个双击datagridview单元格的事件，其中我将单元格值输入到我的主题名称文本框和主题短名称文本框，如果我双击它也是成功的。

 [ 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]

我的问题是，如何在将值添加到文本框并更新它们，提交更改并刷新我的datagridview后，如何为数据库创建更新按钮？

Answer 1

假设您的输入未绑定到数据集，您只需要从数据库中检索现有记录，更新记录并再次保存。这样的事情应该有效：

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

谢谢Haim我用LinqtoSQL解决了这个问题

 [ 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]

感谢StackOverflow和MSDN提供指导

如何为数据库创建更新按钮？

2 个答案: