Vb.net 我怎样才能把一个额外的价值？

我有这样一个表（

DataGridView

）：

Col1 | Col2 | Col3

3    | Mars | Regular

这是我的密码：

For a As Integer = 0 To Form3.DataGridView1.Rows.Count - 1
    For b As Integer = 0 To Form3.DataGridView1.Rows.Count - 1
        For c As Integer = 0 To Form3.DataGridView1.Rows.Count - 1
            If Form3.DataGridView1.Rows(c).Cells(2).Value = "Regular" Then
                If Form3.DataGridView1.Rows(b).Cells(1).Value = Form3.MetroComboBox7.Items(0) Then
                    fair = 7 * Form3.DataGridView1.Rows(a).Cells(0).Value
                    Label1.Text += fair
                End If
            End If
        Next
    Next
Next

---

我想设置，如果在

Col3

上选择Regular，在

Col2

上选择Mars，则值为7，它将乘以行

Col1

，并且每行都相同。

我认为应该使用事件

dtgv.CellMouseClick

然后你创造你想要的条件。我举一个例子：

Public Sub event_select() Handles dtgv.CellMouseClick
        Dim row As Integer = dtgv.CurrentRow.Index()
        ' If the column 2 and 3 are selected
        If dtgv.Rows(row).Cells(1).Selected = True And dtgv.Rows(row).Cells(2).Selected = True Then
            ' If the value of the 2nd column is Mars and the value of the 3rd column is Regular
            If dtgv.Rows(row).Cells(1).Value = "Mars" And dtgv.Rows(row).Cells(2).Value = "Regular" Then
                Label1.Text = 7 * dtgv.Rows(row).Cells(0).Value
            End If
        End If
    End Sub

---

您还应该检查是否没有选择其他行的单元格。

所有行的一个循环足以计算所有行的“公平”

Const REGULAR_VALUE As String = "Regular"
Const FAIR_COEFFICENT As Integer = 7
Dim fairSum As Integer = 0

For Each row As DataGridViewRow in DataGridView1.Rows
    If REGULAR_VALUE.Equals(row.Cells(2).Value.ToString()) = False Then Continue For
    If Equals(MetroComboBox7.Items(0), row.Cells(1).Value) = False Then Continue For

    Dim col1Value As Integer = Integer.Parse(row.Cells(1).Value)
    Dim fair As Integer = col1Value  * FAIR_COEFFICENT 
    fairSum += fair
Next

Label1.Text = fairSum.ToString()

并在项目中或至少在代码文件（文件的第一行）中设置

选项Strict On

。
这将通过在编译时提供有关可能的类型转换错误的快速反馈来节省时间

创建以强类型方式表示数据的类

Public Class Ticket
    Public Property Passenger As Integer
    Public Property Destination As String
    Public Property Status As String     
End Class

然后，您可以在表单中以简单的方式向DataGridView添加行

Public Class YourForm
    Private _tickets As New BindigList(Of Ticket)()

    Public Sub New()
        InitializeComponent() ' Forms required method

        DataGridView1.DataSource = _tickets 
    End Sub 

    Private Sub Populate(passenger As Integer, destination As String, Status As String)
        Dim newTicket As New Ticket With
        {
            .Passenger = passenger,
            .Destination = destination,
            .Status = Status,
        }
        _ticket.Add(newTicket)
    End Sub  

    'Then you can loop all rows with correct types
    Private Sub Calculate()
        Dim fairSum As Integer = 0

        For Each ticket As Ticket in _tickets
            If REGULAR_VALUE.Equals(ticket.Status) = False Then Continue For
            If ticket.Destination.Equals(MetroComboBox7.Items(0)) = False Then Continue For

            Dim fair As Integer = ticket.Passenger * FAIR_COEFFICENT 
            fairSum += fair
        Next

        Label1.Text = fairSum.ToString()
    End Sub     
End Class

---

为什么要在

DataGridView

行中循环三次？你不应该删除b的循环

和c的循环
，并像这样引用
a
。行（a）
？我正在尝试循环3列中的每个值，你不需要这样做。只需对As Integer循环使用
，并在所有
行（a）
上引用
a
。摆脱b
的
和c
的
循环。如何在没有事件的情况下做到这一点？加载时加载表单时，您没有选定的单元格，对吗？您也可以将表单3的事件触发到其他表单，并显示“指定的强制转换无效”。您应该给他错误发生的行@NeCatDim col1Value As Integer=DirectCast（row.cells（0）.Value，Integer）。这行显示“指定的强制转换无效”@NeCat第一列中的值的类型是什么？私有子填充（乘客为字符串，目的地为字符串，状态为字符串）Dim row As String（）=New String（）{乘客，目的地，状态}DataGridView1.Rows.Add（row）这是我用于每列的方法，列1的组合框具有整数值