wblprojects.vb

数据库学习的绝好例子简单的数据库经典入门

Public Class WBLProjects
    Implements IDisposable

    'Private variables and objects
    Private objWDAProject As WroxDataAccess.WDAProjects

    Private disposed As Boolean = False

#Region " Constructor and Destructor "
    Public Sub New(ByVal Company As String, ByVal Application As String)
        objWDAProject = New WroxDataAccess.WDAProjects(Company, Application)
    End Sub

    ' IDisposable
    Private Overloads Sub Dispose(ByVal disposing As Boolean)
        If Not Me.disposed Then
            If disposing Then
                ' TODO: put code to dispose managed resources
            End If

            objWDAProject.Dispose()
            objWDAProject = Nothing
        End If
        Me.disposed = True
    End Sub
#End Region

#Region " IDisposable Support "
    ' This code added by Visual Basic to correctly implement the disposable pattern.
    Public Overloads Sub Dispose() Implements IDisposable.Dispose
        ' Do not change this code.  Put cleanup code in Dispose(ByVal disposing As Boolean) above.
        Dispose(True)
        GC.SuppressFinalize(Me)
    End Sub

    Protected Overrides Sub Finalize()
        ' Do not change this code.  Put cleanup code in Dispose(ByVal disposing As Boolean) above.
        Dispose(False)
        MyBase.Finalize()
    End Sub
#End Region

#Region " Public Project Functions "
    Public Function GetProjects() As DataSet
        Try
            'Call the data component to get all projects
            GetProjects = objWDAProject.GetProjects
        Catch ExceptionErr As Exception
            Throw New System.Exception(ExceptionErr.Message, _
                ExceptionErr.InnerException)
        End Try
    End Function

    Public Function GetProject(ByVal ProjectID As Guid) As DataSet
        Try
            'Call the data component to get a specific project
            GetProject = objWDAProject.GetProject(ProjectID)
        Catch ExceptionErr As Exception
            Throw New System.Exception(ExceptionErr.Message, _
                ExceptionErr.InnerException)
        End Try
    End Function

    Public Function GetNewProjectDS() As DataSet
        Try
            'Instantiate a new DataSet object
            GetNewProjectDS = New DataSet

            'Create a DataTable object
            Dim objDataTable As DataTable = GetNewProjectDS.Tables.Add("Project")

            'Create a DataColumn object
            Dim objDataColumn As DataColumn

            'Instantiate a new DataColumn and set its properties
            objDataColumn = New DataColumn("ProjectID", _
                Type.GetType("System.Guid"))
            objDataColumn.AllowDBNull = False

            'Add the column to the table
            objDataTable.Columns.Add(objDataColumn)

            'Instantiate a new DataColumn and set its properties
            objDataColumn = New DataColumn("ProjectName", _
                Type.GetType("System.String"))
            objDataColumn.AllowDBNull = False
            objDataColumn.MaxLength = 50

            'Add the column to the table
            objDataTable.Columns.Add(objDataColumn)

            'Instantiate a new DataColumn and set its properties
            objDataColumn = New DataColumn("ProjectDescription", _
                Type.GetType("System.String"))

            'Add the column to the table
            objDataTable.Columns.Add(objDataColumn)

            'Instantiate a new DataColumn and set its properties
            objDataColumn = New DataColumn("SequenceNumber", _
                Type.GetType("System.Byte"))
            objDataColumn.AllowDBNull = False

            'Add the column to the table
            objDataTable.Columns.Add(objDataColumn)
        Catch ExceptionErr As Exception
            Throw New System.Exception(ExceptionErr.Message, _
                ExceptionErr.InnerException)
        End Try
    End Function

    Public Function AddProject(ByVal Project As DataSet) As Boolean
        Try
            'Call the data component to add the project
            Return objWDAProject.AddProject(Project)
        Catch ExceptionErr As Exception
            Throw New System.Exception(ExceptionErr.Message, _
                ExceptionErr.InnerException)
        End Try
    End Function

    Public Function UpdateProject(ByVal Project As DataSet) As Boolean
        Try
            'Call the data component to update the project
            Return objWDAProject.UpdateProject(Project)
        Catch ExceptionErr As Exception
            Throw New System.Exception(ExceptionErr.Message, _
                ExceptionErr.InnerException)
        End Try
    End Function

    Public Function DeleteProject(ByVal ProjectID As Guid) As Boolean
        Try
            'Call the data component to delete the project
            Return objWDAProject.DeleteProject(ProjectID)
        Catch ExceptionErr As Exception
            Throw New System.Exception(ExceptionErr.Message, _
                ExceptionErr.InnerException)
        End Try
    End Function
#End Region
End Class