mysql - 如何计算、比较和添加 DataGridView 行中的值？

Question

我需要什么才能从 DataGridView 计算、比较和添加值？

这是我用于插入/填充 Datagridview 的代码行

Sub display()
    Dim temp As Double = 0
    'count is my ID that counts the number of tickets from 1 and so on - count is also primary key in my database..
    Dim lt As String = "select count as Tickets, mname as Movie, mtime as Time, mprice as Price, mimg as Photo from tickets order by count asc" 'add desc for descending order/ asc for ascending (order by vlanme desc)
    Dim da As New MySqlDataAdapter(lt, con)
    con.Open()

    Dim ds As New DataSet
    da.Fill(ds, "settings")
    da.Dispose()
    DataGridView1.DataSource = ds.Tables(0)
    con.Close()
End Sub

我想要的是计算我的 Datagridview 有多少行

我还想比较两行之间的值

我还想添加两行的值

我只想计算我有多少张票，比较行(1)和行(2)等的名称，并将行(1)等中的价格添加为总计

(我想在不使用 .SelectedCell 方法的情况下执行此操作，因为我将一次性计算、比较、添加它们 - datagridview 中的所有现有数据)

谢谢!

Answer 1

我已经找到了答案

Dim bs As New BindingSource
    Dim dr As MySqlDataReader
    Dim rowcount As Integer = DataGridView1.Rows.Count
    Dim moviecount As Integer = 0
    Dim price As Integer = 0
    For index As Integer = 0 To rowcount
        Try
            If con.State = ConnectionState.Closed Then
                con.Open()
                Dim query As String = "select * from tickets where count = '" & index & "'"
                Dim cmd As New MySqlCommand(query, con)
                dr = cmd.ExecuteReader
                While dr.Read
                    If moviecount = 0 Then
                        movie = dr.GetString("mname")
                        moviecount += 1
                    End If

                    If moviecount > 0 Then
                        If movie = dr.GetString("mname") Then
                            price += dr.GetInt32("mprice")
                        Else
                            MsgBox(movie & " has a total sales of : " & price, MsgBoxStyle.Information, "System Checked!")
                            price = 0
                            price += dr.GetInt32("mprice")
                            moviecount = 0
                        End If
                    End If
                End While
            End If
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
        con.Close()
    Next
    MsgBox(movie & " has a total sales of : " & price, MsgBoxStyle.Information, "System Checked!")

dr.getString("来自数据库的变量") 或 dr.getInt32("来自数据库的变量")

这可以让您选择将数据库中的哪个值传输到您设置为 String 或 Int 的 Varname(如果添加循环，您还想要哪一行)