我是否兩次加載數據表並使用布爾值更新行項目

Question

我在模塊中調用以下函數

公共函數GetExcelData（ByVal ExcelFile As String）As System.Data.DataTable

然后我有以下代碼

            If openFileDialog1.ShowDialog() = System.Windows.Forms.DialogResult.OK Then
            gblCompName = openFileDialog1.FileName
        End If

        Dim reader As New DataTableReader(GetExcelData(gblCompName))
        Dim table As New DataTable

        table.Load(reader)
        table.Columns.Add("Single", GetType(Boolean), False)
        table.Columns.Add("CouplesInFinal", GetType(Int32))
        table.Columns.Add("EvtNum", GetType(String))
        table.Columns.Add("EvtStruct", GetType(Int32))
        table.Columns.Add("EvtCplID", GetType(Int32))
        table.Columns.Add("CouplesInClass", GetType(Int32))
        table.Columns.Add("Valid", GetType(Boolean), True)

        Dim result() As DataRow = table.Select("[class]" Like "Single")
        For Each row In result
            If row.Item("Class") Like "Single" Then
                table.Rows(0)("Single") = True
            End If
        Next

        DataGridView1.DataSource = table

我的邏輯告訴我，我要兩次加載表，並且數據行字段“ Single”是布爾值，如果字符串字段“ class”類似於“ Single”，則我嘗試將其更新為True

我意識到這是兩個問題，但是加載速度似乎很慢，而且都是一種形式的程序。 任何對此的建議將非常受歡迎，謝謝

Answer 1

Dim reader As New DataTableReader(GetExcelData(gblCompName))
Dim table As New DataTable

如果沒有看到GetExcelData，很難說您是否填寫兩次。 如果此函數返回填充的DataTable，則

Dim table as DataTable = GetExcelData(gblCompName)

並刪除table.Load和DataReader。 這是我針對示例數據庫更新DataTable的版本。

Private Sub TestDataTableUpdate()
        Try
            Using cmd As New SqlCommand("Select * From Coffees", CoffeeCn)
                Dim dt As New DataTable
                CoffeeCn.Open()
                Using dr As SqlDataReader = cmd.ExecuteReader
                    dt.Load(dr)
                End Using
                CoffeeCn.Close()
                For index As Integer = 0 To dt.Rows.Count - 1
                    If dt.Rows(index)("Name").ToString = "Cinnamon Stick" Then
                        dt.Rows(index)("Roast") = "N/A"
                    End If
                Next
                'The above does not update the database
                Dim da As New SqlDataAdapter(cmd) 'provides the connection and Select command
                Dim sqlCB As New SqlCommandBuilder(da) 'Associates the DataAdapter to the command builder
                sqlCB.GetUpdateCommand() 'Retrieve the update command for the DataAdapter
                'Note: the DataAdapter opens and closes the connection for you
                da.Update(dt) 'This updates the database by finding the changed rows in the datatable
                'and running the Update command
                dt.AcceptChanges() 'Reset the row status to unchanged
                DataGridView1.DataSource = dt
            End Using
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        Finally
            CoffeeCn.Close()
        End Try
    End Sub

PS。 我也是自學成才的。

Answer 2

我要工作的表更新方法是

                Dim i As Integer = 0
            For i = 0 To table.Rows.Count - 1
                If table.Rows(i)("Class") Like "*Single*" Then
                    table.Rows(i)("Single") = True
                End If
            Next

我在此線表上刪除了“，False”。Columns.Add（“ Single”，GetType（Boolean）