datasetform.vb

Microsoft Mobile Development Handbook的代码,有C#,VB,C++的

Imports System.Text

Public Class DataSetForm

    Private Sub MenuItem1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuItem1.Click
        DoStuffWithDataSet()
    End Sub

    Private Sub DoStuffWithDataSet()
        ' Create an instance of the strongly-typed DataSet
        Dim productsDS As ProductsDataSet = New ProductsDataSet()

        ' Create a table adapter for product categories
        Dim catTA As ProductsDataSetTableAdapters.ProductCategoryTableAdapter = _
                New ProductsDataSetTableAdapters.ProductCategoryTableAdapter()
        ' ... and for products
        Dim prodTA As ProductsDataSetTableAdapters.ProductTableAdapter = _
                New ProductsDataSetTableAdapters.ProductTableAdapter()

        ' FIRST: Get any existing data in these tables from the database
        ' Fill the ProductCategories table in the DataSet with data from the database
        catTA.Fill(productsDS.ProductCategory)
        ' .. and the Products. 
        prodTA.Fill(productsDS.Product)

        ' Report count of records to the screen...
        ReportRecords(productsDS)

        ' SECOND: Add some product categories
        ' To make sure we don't duplicate names, productCategory.Name has a unique constraint
        Try
            productsDS.ProductCategory.AddProductCategoryRow("Rock Climbing Equipment")
            productsDS.ProductCategory.AddProductCategoryRow("Scuba Diving Equipment")

            ' Update to write changes back to the database
            catTA.Update(productsDS.ProductCategory)
            textBox1.Text += "\r\nProduct Categories added.\r\n"
        Catch
            ' If the categories already exist, just continue
            textBox1.Text += "\r\nProduct Category addition failed, items already exist.\r\n"
        End Try

        ' THIRD: Add some products in the category with categoryID of 1
        Dim prodCatRow As ProductsDataSet.ProductCategoryRow = Nothing
        For Each row As ProductsDataSet.ProductCategoryRow In productsDS.ProductCategory.Rows
            If row.ProductCategoryID = 1 Then
                prodCatRow = row
                Exit For
            End If
        Next
        System.Diagnostics.Debug.Assert(Not prodCatRow Is Nothing, "Logic erro: No ProductCategory '1' found")
        productsDS.Product.AddProductRow("Contoso Single Rope", "Red/Blue", 155.95, "60m", prodCatRow)
        productsDS.Product.AddProductRow("Contoso Rock Shoes", "Black", 89.95, "8", prodCatRow)

        ' Write to database
        prodTA.Update(productsDS.Product)
        textBox1.Text += "\r\nProducts added.\r\n"

        ' Report count of records to screen...
        ReportRecords(productsDS)
    End Sub

    Private Sub ReportRecords(ByVal productsDS As ProductsDataSet)
        Dim sb As StringBuilder = New StringBuilder(textBox1.Text)
        sb.Append("There are currently ")
        sb.Append(productsDS.ProductCategory.Rows.Count)
        sb.Append(" product categories.\r\n")
        sb.Append("There are currently ")
        sb.Append(productsDS.Product.Rows.Count)
        sb.Append(" products.\r\n")
        textBox1.Text = sb.ToString()
    End Sub


End Class