使用Linq和MySql对来自Datagridview1（Table1）的值求和并将其保存到Datagridview2（Table2）

Question

我正在尝试对Datagridview1(Table1)的值求和并将其保存到Datagridview2(Table2)

两个DGVs是Databound两者具有相同的2列Name, Quantity 。

在Childform1(DGV1)我有一个Textbox1和一个Post按钮。

用户必须在Textbox1上输入一个Name ，然后单击Post ，然后必须对DGV1上的所有“ Quantity ”进行汇总，其Name与在Textbox1输入的Name相同。

例如：

表格1

Name | Quantity
 a       10
 b        5
 a       10
 b        5

按POST按钮后

表2

Name | Quantity
 a        20
 b        10

代号

    Dim occurences As New Dictionary(Of String, Double)
    Dim oTempObjects As New List(Of DataGridViewRow)

    MasterForm.oTransferRows = oTempObjects

    For Each xRow As DataGridViewRow In Datagridview1.Rows

        If (Not xRow.Cells("GVName").Value Is Nothing AndAlso xRow.Cells("GVName").Value.ToString() = TextBox1.Text) Then

            oTempObjects.Add(xRow)
        End If
    Next

    Dim _Name As New List(Of String)

    For Each xRows In MasterForm.oTransferRows

        _Name.Add("'" & xRows.Cells("GVName").Value.ToString() & "'")


        Dim inClause1 As String = String.Join(",", _Name.ToArray())
        Dim _sqlUpdate As String = String.Format("UPDATE tested SET Posted = @Posted WHERE Name IN ({0})", inClause1)

        Using _conn As New MySqlConnection("Server = localhost; Username= root; Password =; Database = test")
            Using _commm As New MySqlCommand()
                With _commm

                    .CommandText = _sqlUpdate
                    .Connection = _conn
                    .CommandType = CommandType.Text
                    .Parameters.AddWithValue("@Posted", "Yes")

                End With
                Try

                    _conn.Open()
                    _commm.ExecuteNonQuery()

                Catch ex As MySqlException

                    MsgBox(ex.StackTrace.ToString)

                End Try

                _conn.Close()

            End Using
        End Using

        If (occurences.ContainsKey(xRows.Cells(1).Value.ToString())) Then

            occurences(xRows.Cells(1).Value.ToString()) = Double.Parse(occurences(xRows.Cells(1).Value.ToString()).ToString()) + Double.Parse(xRows.Cells(4).Value.ToString())

        Else

            occurences.Add(xRows.Cells(1).Value.ToString(), Double.Parse(xRows.Cells(4).Value.ToString()))
        End If

    Next

    For Each KVP As KeyValuePair(Of String, Double) In occurences
        oChildForm2.DataGridView2.Rows.Add(New Object() {KVP.Key, KVP.Value})
    Next

    Dim xlist As List(Of KeyValuePair(Of String, Double)) = occurences.ToList

    For Each pair As KeyValuePair(Of String, Double) In occurences


        Dim oUpdateString = String.Format("Insert Into testing (Name, Quantity) VALUES (@iName, @iQty)")
        Using _conn As New MySqlConnection("Server = localhost; Username= root; Password =; Database = test")
            Using _commm As New MySqlCommand()
                With _commm

                    .CommandText = oUpdateString
                    .Connection = _conn
                    .CommandType = CommandType.Text
                    .Parameters.AddWithValue("@iName", pair.Key)
                    .Parameters.AddWithValue("@iQty", pair.Value)
                End With
                Try

                    _conn.Open()
                    _commm.ExecuteNonQuery()

                Catch ex As MySqlException

                    MsgBox(ex.StackTrace.ToString)

                End Try

                _conn.Close()

            End Using
        End Using
    Next

第一次单击时，此代码仅将DGV1上的相同名称DGV1 ，然后将其保存在DGV2 。

但是例如，我在DGV1上添加了另一个同名数据，

我希望将新添加的数据的数量添加到DGV2上现有数据的当前总和中。

一点帮助也真的很棒。**

例如：

表2

Name | Quantity
 a       20
 b       10

然后我在表1上添加数据

表格1

Name | Quantity
  a       20
  b       10

按下后

表2

Name | Quantity
 a        40
 b        20

Answer 1

遍历行时检查“已发布”列，以查看是否已发布行：

For Each xRows In MasterForm.oTransferRows.Where(Function(x) x.Cells("Posted").Value.ToString() = "No")

然后使用以下psuedo-logic编写代码：

 'code to select data - select name from testing where name = 'Product1'
 'if(dr.Read())
 'update goes here
 'Else
 ' insert goes here
 'End if