find control in FlowLayoutPanel

Question

hi

I added PictureBox to the FlowLayoutPanel Each image takes a value from the datatable by tag = id column. What I want is to choose the image that has the number that I specify

my code Does not select any image

For Each item As Control In FlowLayoutPanel.Controls

        If TypeOf item Is PictureBox Then
            If item.Tag = "3" Then
                item.BackgroundImage = Nothing
                item.Select()
            End If
        End If
    Next

Answer 1

Hello,

I would use a custom PictureBox so there is no need to cast.

Public Class MyPictureBox
    Inherits PictureBox
    ''' <summary>
    ''' Primary key from database or DataTable
    ''' </summary>
    ''' <returns></returns>
    Public Property PrimaryKey() As Integer

End Class

Simple demo to create one (and you can get it from the toolbox rather than hand code it)

Dim myBox = New MyPictureBox
myBox.PrimaryKey = 3

Find by primary key which is hard code here but the 3 can come from where ever. I check to see if it's found then for this simple example remove the background image.

Dim pb = FlowLayoutPanel1.Controls.OfType(Of MyPictureBox).FirstOrDefault(Function(pbox) pbox.PrimaryKey = 3)
If pb IsNot Nothing Then
    pb.BackgroundImage = Nothing
End If

Second code sample

Public Class Form1

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim pb = FlowLayoutPanel1.Controls.OfType(Of MyPictureBox).FirstOrDefault(Function(pbox) pbox.PrimaryKey = 3)
        If pb IsNot Nothing Then
            Text = $"From button click event: {pb.PrimaryKey}"
        End If
    End Sub

    Private Sub Form1_Shown(sender As Object, e As EventArgs) Handles Me.Shown
        FlowLayoutPanel1.Controls.OfType(Of MyPictureBox).ToList().ForEach(
            Sub(pb)
                AddHandler pb.Click, AddressOf MyPictureBox_Click
            End Sub)
    End Sub

    Private Sub MyPictureBox_Click(sender As Object, e As EventArgs)
        Dim pb As MyPictureBox = CType(sender, MyPictureBox)

        Text = $"From Picture click event: {pb.PrimaryKey}"

        If pb.BorderStyle = BorderStyle.None Then
            pb.BorderStyle = BorderStyle.Fixed3D
        Else
            pb.BorderStyle = BorderStyle.None
        End If

    End Sub
End Class