Question

我想在pb1（图片框）中绘制椭圆，但椭圆的数量取决于查询将给出的内容。通常，它超过1.我已经有一个代码，但它只绘制一个椭圆。

我想使用数组，但我不知道如何。任何帮助/协助将不胜感激。谢谢

Sub getdots()
    Try
        Call MyConnection()
        Sql = "select l.lot_no, l.lot_x, l.lot_y FROM lot_details AS l, area as a, type as t where l.type_no=t.type_no and t.AREA_NO=a.AREA_NO and a.AREA_NO=@Anum AND l.LOT_STATE='available'"
        Dim cmd As New MySqlCommand(Sql, Con)
        With cmd
            .CommandText = Sql
            .Connection = Con
            .Parameters.AddWithValue("@Anum", frmvacantlots.cboareano.Text)
            .ExecuteNonQuery()
        End With
        Dim reader As MySqlDataReader
        reader = cmd.ExecuteReader
        If reader.Read Then
            Try

                x = reader.GetString(1)
                y = reader.GetString(2)
            Catch ex As Exception
                MsgBox(ex.Message)
            End Try
        End If
    Catch ex As Exception
        MsgBox(ex.Message)
    End Try
    Con.Close()
End Sub


Private Sub pb1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles pb1.Paint
    e.Graphics.FillEllipse(Brushes.Red, x - 5, y - 5, 10, 10)
    getdots()
End Sub

Answer 1

创建一个列表来存储所有值：

Private points As New List(Of Point)

阅读查询中的所有要点：

While reader.Read
    Try
        x = reader.GetInt32(1)
        y = reader.GetInt32(2)
        points.Add(New Point(x, y))
    Catch ex As Exception
        MsgBox(ex.Message)
    End Try
End While

对于 points 中的每个值，绘制就像您已经为一个值绘制的那样：

Private Sub pb1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles pb1.Paint
    points.ForEach(Sub(p) e.Graphics.FillEllipse(Brushes.Red, p.X - 5, p.Y - 5, 10, 10))
    getdots()
End Sub

如何在绘图点创建数组

1 个答案: