当我在图表上使用鼠标时，如何在图表区域获得自定义 X 值

Question

我正在制作报告图表，我的问题是当我在图表（注释）上移动鼠标时如何获取图表的 x 值（图表区域的自定义值）？

过去 2 天我已经这样做了，但我仍然不知道如何获取图表的 x 值。我尝试使用图表上的相关代码，但我仍然没有得到想要的结果

Private Sub cmdGenChart_Click(sender As Object, e As EventArgs) Handles cmdGenChart.Click
    Access.AddParam("@dt1", DateTimePicker1.Value.AddDays(-1).ToString)
    Access.AddParam("@dt2", DateTimePicker2.Value.ToString)

    Access.ExecQuery("SELECT [Flood_ID], [Flood_Level], [Flood_Time], [Flood_Date] " & _
                     "FROM WaterLevel " & _
                     "WHERE [Flood_Date] BETWEEN @dt1 AND @dt2 " & _
                     "ORDER BY [Flood_ID] ASC")

    Dim checkDate As DateTime = DateTimePicker1.Value

    For Each r As DataRow In Access.dt.Rows

        Chart1.ChartAreas(0).AxisX.CustomLabels.Add(Counter - 1, Counter + 1, r("Flood_Time"))

        Chart1.Series("Water Level").Points.AddXY(Counter, r("Flood_Level"))

        Counter += 1
    Next

    Dim PC As New CalloutAnnotation

    With PC
        Chart1.Annotations.Add(PC)
    End With
End Sub

Private Sub Chart1_MouseMove(sender As Object, e As MouseEventArgs) Handles Chart1.MouseMove

    Dim result As HitTestResult = Chart1.HitTest(e.X, e.Y)

    If result.ChartElementType = ChartElementType.DataPoint Then
        Chart1.Series(0).Points(result.PointIndex).XValue.ToString()

        Dim thisPt As New PointF(CSng(Chart1.Series(0).Points(result.PointIndex).XValue),
                               CSng(Chart1.Series(0).Points(result.PointIndex).YValues(0)))

        Dim ta As New CalloutAnnotation

        With ta
            .AnchorDataPoint = Chart1.Series(0).Points(result.PointIndex)
            .Text = "Water Level: " & thisPt.Y.ToString & vbCrLf & "Time: " & DateTime.FromOADate(thisPt.X).ToShortTimeString

            If thisPt.Y.ToString <= 20 And thisPt.Y Then
                .ForeColor = Color.Green
                .Font = New Font("Tahoma", 10, FontStyle.Bold)
            ElseIf thisPt.Y.ToString <= 60 Then
                .ForeColor = Color.Orange
                .Font = New Font("Tahoma", 10, FontStyle.Bold)
            ElseIf thisPt.Y.ToString > 60 Then
                .ForeColor = Color.Red
                .Font = New Font("Tahoma", 10, FontStyle.Bold)
            End If

        End With

        Chart1.Annotations(0) = ta
        Chart1.Invalidate()
    End If
End Sub

我要的是Time的值等于它下面对应x值的值

图片上：
水位：15
时间：12:00上午

期望的结果：
水位：15
时间：6:21上午

http://prntscr.com/m0p4xb

Answer 1

想了很久，我找到的解决方案是将我的计数器设置为等于我在数据库上的主键的值，并将其设置为绑定在图表上，然后我只会加载它我的 SQL 命令就成功了。

全局变量

    Dim counter as Double = 1

生成图表按钮

Private Sub cmdGenChart_Click(sender As Object, e As EventArgs) Handles cmdGenChart.Click
    Access.AddParam("@dt1", DateTimePicker1.Value.AddDays(-1).ToString)
    Access.AddParam("@dt2", DateTimePicker2.Value.ToString)


    Access.ExecQuery("SELECT [Flood_ID], [Flood_Level], [Flood_Time], [Flood_Date] " & _
                     "FROM WaterLevel " & _
                     "WHERE [Flood_Date] BETWEEN @dt1 AND @dt2 " & _
                     "ORDER BY [Flood_ID] ASC")

    For Each r As DataRow In Access.dt.Rows

        Counter = r("Flood_ID")

        Chart1.ChartAreas(0).AxisX.CustomLabels.Add(Counter - 1, Counter + 1, r("Flood_Time"))

        Chart1.Series("Water Level").Points.AddXY(Counter, r("Flood_Level"))

        Counter += 1
    Next

    Dim PC As New CalloutAnnotation

    With PC
        Chart1.Annotations.Add(PC)
    End With

End Sub

图表鼠标移动

Private Sub Chart1_MouseMove(sender As Object, e As MouseEventArgs) Handles Chart1.MouseMove

    Dim result As HitTestResult = Chart1.HitTest(e.X, e.Y)

    If result.ChartElementType = ChartElementType.DataPoint Then
        Chart1.Series(0).Points(result.PointIndex).XValue.ToString()

        Access.AddParam("@pos", Chart1.Series(0).Points(result.PointIndex).XValue)
        Access.AddParam("@level", Chart1.Series(0).Points(result.PointIndex).YValues(0))

        Access.ExecQuery("SELECT [Flood_ID], [Flood_Level], [Flood_Time] " & _
                         "FROM WaterLevel " & _
                         "WHERE [Flood_ID] = @pos AND [Flood_Level] = @level ")

        Dim r As DataRow = Access.dt.Rows(0)

        Dim ta As New CalloutAnnotation

        With ta
            .AnchorDataPoint = Chart1.Series(0).Points(result.PointIndex)
            .Text = "Water Level: " & r("Flood_Level") & vbCrLf & "Time: " & r("Flood_Time")

        End With

        Chart1.Annotations(0) = ta
        Chart1.Invalidate()
    End If
End Sub

这是结果： http://prntscr.com/m2xpnf

当我在图表上使用鼠标时，如何在图表区域获得自定义 X 值

How do I get the Custom X Values on the Chart Areas when I use my mouse on the chart

vb.net

charts

linechart