admin.vb

数据库学习的绝好例子简单的数据库经典入门

                    cboUserManager.SelectedIndex = -1
                    txtUserUpdateDate.Text = String.Empty

                    'Reload the Users list
                    LoadUsers()
            End Select

            'Display a message that the record was added
            ToolStripStatus.Text = "Record Added"
        Catch ExceptionErr As Exception
            MessageBox.Show(ExceptionErr.Message, strAppTitle)
        End Try
    End Sub

    Private Sub ActionUpdate()
        Try
            'Update database row based on the active screen
            Select Case strActiveScreen
                Case "Projects"
                    'Initialize a new instance of the business logic component
                    Using objProjects As New WroxBusinessLogic.WBLProjects( _
                        strCompany, strApplication)
                        'Get a new Project DataSet
                        objDataSet = objProjects.GetNewProjectDS()
                        'Initialize a datarow object from the Project DataSet
                        Dim objDataRow As Data.DataRow = _
                            objDataSet.Tables("Project").NewRow
                        'Set the values in the DataRow
                        objDataRow.Item("ProjectID") = New Guid(txtProjectID.Text)
                        objDataRow.Item("ProjectName") = txtProjectName.Text
                        objDataRow.Item("ProjectDescription") = _
                            txtProjectDescription.Text
                        objDataRow.Item("SequenceNumber") = _
                            CType(txtSequenceNumber.Text, Integer)
                        'Add the DataRow to the DataSet
                        objDataSet.Tables("Project").Rows.Add(objDataRow)
                        'Update the Project in the database
                        If Not objProjects.UpdateProject(objDataSet) Then
                            Throw New Exception("Update Project Failed")
                        End If
                    End Using

                    'Clear the input fields
                    txtProjectID.Text = String.Empty
                    txtProjectName.Text = String.Empty
                    txtProjectDescription.Text = String.Empty
                    txtSequenceNumber.Text = String.Empty
                    txtProjectUpdateDate.Text = String.Empty

                    'Reload the Projects list
                    LoadProjects()

                Case "Groups"
                    'Initialize a new instance of the business logic component
                    Using objGroups As New WroxBusinessLogic.WBLGroups( _
                        strCompany, strApplication)
                        'Get a new Group DataSet
                        objDataSet = objGroups.GetNewGroupDS()
                        'Initialize a datarow object from the Group DataSet
                        Dim objDataRow As Data.DataRow = _
                            objDataSet.Tables("Group").NewRow
                        'Set the values in the DataRow
                        objDataRow.Item("GroupID") = New Guid(txtGroupID.Text)
                        objDataRow.Item("GroupName") = txtGroupName.Text
                        objDataRow.Item("GroupDescription") = _
                            txtGroupDescription.Text
                        'Add the DataRow to the DataSet
                        objDataSet.Tables("Group").Rows.Add(objDataRow)
                        'Add the Group to the database
                        If Not objGroups.UpdateGroup(objDataSet) Then
                            Throw New Exception("Update Group Failed")
                        End If
                    End Using

                    'Clear the input fields
                    txtGroupID.Text = String.Empty
                    txtGroupName.Text = String.Empty
                    txtGroupDescription.Text = String.Empty
                    txtGroupUpdateDate.Text = String.Empty

                    'Reload the Groups list
                    LoadGroups()

                Case "Group Projects"
                    'Turn the loading flag on so no items are processed
                    blnLoading = True
                    Call ActionAdd()

                Case "Roles"
                Case "Users"
            End Select

            'Display a message that the record was update
            ToolStripStatus.Text = "Record Updated"
        Catch ExceptionErr As Exception
            MessageBox.Show(ExceptionErr.Message, strAppTitle)
        End Try
    End Sub

    Private Sub ActionDelete()
        Try
            'Delete database row based on the active screen
            Select Case strActiveScreen
                Case "Projects"
                    'Initialize a new instance of the business logic component
                    Using objProjects As New WroxBusinessLogic.WBLProjects( _
                        strCompany, strApplication)
                        'Delete the project
                        If Not objProjects.DeleteProject( _
                            New Guid(txtProjectID.Text)) Then
                            Throw New Exception("Delete Project Failed")
                        End If
                    End Using

                    'Clear the input fields
                    txtProjectID.Text = String.Empty
                    txtProjectName.Text = String.Empty
                    txtProjectDescription.Text = String.Empty
                    txtSequenceNumber.Text = String.Empty
                    txtProjectUpdateDate.Text = String.Empty

                    'Reload the Projects list
                    LoadProjects()

                Case "Groups"
                    'Initialize a new instance of the business logic component
                    Using objGroups As New WroxBusinessLogic.WBLGroups( _
                        strCompany, strApplication)
                        'Delete the group
                        If Not objGroups.DeleteGroup( _
                            New Guid(txtGroupID.Text)) Then
                            Throw New Exception("Delete Group Failed")
                        End If
                    End Using

                    'Clear the input fields
                    txtGroupID.Text = String.Empty
                    txtGroupName.Text = String.Empty
                    txtGroupDescription.Text = String.Empty
                    txtGroupUpdateDate.Text = String.Empty

                    'Reload the Groups list
                    LoadGroups()

                Case "Group Projects"
                    'Initialize a new instance of the business logic component
                    Using objGroups As New WroxBusinessLogic.WBLGroups( _
                        strCompany, strApplication)
                        'Delete the group projects
                        objGroups.DeleteGroupProjects( _
                            New Guid( _
                            cboGroups.SelectedItem.Item("GroupID").ToString))
                    End Using

                    'Clear previous bindings
                    If Not blnLoading Then
                        lstGroupProjects.DataSource = Nothing
                        lstGroupProjects.DisplayMember = String.Empty
                        lstGroupProjects.ValueMember = String.Empty
                        lstGroupProjects.Items.Clear()
                        blnLoading = True
                        cboGroups.SelectedIndex = -1
                        blnLoading = False
                    End If

                Case "Roles"
                Case "Users"
            End Select

            'Display a message that the record was deleted
            ToolStripStatus.Text = "Record Deleted"
        Catch ExceptionErr As Exception
            MessageBox.Show(ExceptionErr.Message, strAppTitle)
        End Try
    End Sub
#End Region

#Region " Projects Procedures "
    Private Sub LoadProjects()
        'Declare variables
        Dim objListViewItem As ListViewItem

        'Initialize a new instance of the business logic component
        Using objProjects As New WroxBusinessLogic.WBLProjects( _
            strCompany, strApplication)

            Try
                'Clear previous bindings
                lstProjects.DataSource = Nothing
                lstProjects.DisplayMember = String.Empty
                lstProjects.ValueMember = String.Empty

                'Get all projects in a DataSet object
                objProjectsDS = objProjects.GetProjects()

                'Clear previous list
                lvwProjects.Items.Clear()

                'Process all rows
                For intIndex = 0 To objProjectsDS.Tables("Projects").Rows.Count - 1
                    'Create a new listview item
                    objListViewItem = New ListViewItem
                    'Add the data to the listview item
                    objListViewItem.Text = objProjectsDS.Tables( _
                        "Projects").Rows(intIndex).Item("ProjectName")
                    objListViewItem.Tag = objProjectsDS.Tables( _
                        "Projects").Rows(intIndex).Item("ProjectID")
                    'Add the sub items to the listview item
                    objListViewItem.SubItems.Add(objProjectsDS.Tables( _
                        "Projects").Rows(intIndex).Item("ProjectDescription"))
                    objListViewItem.SubItems.Add(objProjectsDS.Tables( _
                        "Projects").Rows(intIndex).Item("SequenceNumber"))
                    objListViewItem.SubItems.Add(Format(objProjectsDS.Tables( _
                        "Projects").Rows(intIndex).Item("LastUpdateDate"), "g"))
                    'Add the listview item to the listview control
                    lvwProjects.Items.Add(objListViewItem)
                Next

                'Rebind ListBox control
                lstProjects.DataSource = objProjectsDS.Tables("Projects")
                lstProjects.DisplayMember = "ProjectName"
                lstProjects.ValueMember = "ProjectID"
            Catch ExceptionErr As Exception
                MessageBox.Show(ExceptionErr.Message, strAppTitle)
            End Try
        End Using

        'Cleanup
        objListViewItem = Nothing

    End Sub

    Private Sub lvwProjects_Click(ByVal sender As Object, _
        ByVal e As System.EventArgs) Handles lvwProjects.Click

        'Initialize a new instance of the business logic component
        Using objProjects As New WroxBusinessLogic.WBLProjects( _
            strCompany, strApplication)

            Try
                'Get the specific project selected in the ListView control
                objDataSet = objProjects.GetProject( _
                    New Guid(lvwProjects.SelectedItems.Item(0).Tag.ToString))

                'Populate the Project Details section
                txtProjectID.Text = _
                    objDataSet.Tables("Project").Rows(0).Item( _
                    "ProjectID").ToString.ToUpper
                txtProjectName.Text = _
                    objDataSet.Tables("Project").Rows(0).Item("ProjectName")
                txtProjectDescription.Text = _
                    objDataSet.Tables("Project").Rows(0).Item( _
                    "ProjectDescription")
                txtSequenceNumber.Text = _
                    objDataSet.Tables("Project").Rows(0).Item("SequenceNumber")
                txtProjectUpdateDate.Text = _
                    objDataSet.Tables("Project").Rows(0).Item("LastUpdateDate")

            Catch ExceptionErr As Exception
                MessageBox.Show(ExceptionErr.Message, strAppTitle)
            End Try
        End Using
    End Sub

    Private Sub lstProjects_MouseDown(ByVal sender As Object, _
        ByVal e As System.Windows.Forms.MouseEventArgs) _
        Handles lstProjects.MouseDown

        If e.Button = MouseButtons.Left Then
            lstProjects.DoDragDrop(objProjectsDS.Tables("Projects").Rows( _
                lstProjects.SelectedIndex)("ProjectID").ToString, _
                DragDropEffects.Copy)
        End If
    End Sub

    Private Sub lstGroupProjects_DragEnter(ByVal sender As Object, _
        ByVal e As System.Windows.Forms.DragEventArgs) _
        Handles lstGroupProjects.DragEnter

        'Exit if nothing has been selected in the cboGroups ComboBox
        If cboGroups.SelectedIndex = -1 Then
            Exit Sub
        End If

        'Now ensure that the drag content is the correct type for this control
        If (e.Data.GetDataPresent(DataFormats.Text)) Then
            'If the item does not already exist then allow the copy
            Dim objDataView As Data.DataView = New _
                Data.DataView(objGroupProjectsDS.Tables("GroupProjects"))
            objDataView.Sort = "ProjectID"
            intIndex = objDataView.Find(e.Data.GetData(DataFormats.Text))
            If intIndex = -1 Then
                e.Effect = DragDropEffects.Copy
            Else
                e.Effect = DragDropEffects.None
            End If
        Else