Creating Multi-Dependent Combo-Boxes

Hi, I am trying to create a user form with multiple combo boxes that are dependent on each other. I have 4 combo boxes and each one is filtering so that the final combo box should have a single result

So far, after a lot of research and help from past posts on this forum, I have managed to get the combo boxes to be dependent on the preceding combo box only. So when I get to the 4th combo box the selections for combo boxes 1 and 2 are ignored and only the selection on combo box 3 is taken into consideration.

I would like to bind these all together so that the filtering on the last combo box is accurate

This is the code I have so far and I also attached the file I'm working on. Additionally I would like to fill the bottom text boxes with the relevant data based on the criteria selected from the combo boxes when the Search button is clicked

[VBA]Option Explicit
Dim i As Integer, a

Private Sub ComboBox1_Change()
a = Sheets("sheet1").Range("table1").Value
With CreateObject("scripting.dictionary")
For i = 2 To UBound(a, 1)
If a(i, 2) = Me.ComboBox1 And Not .Exists(a(i, 3)) Then .Add a(i, 3), a(i, 3) & "_content"
Next
Me.ComboBox2.List = Application.Transpose(.Keys)
End With
With Me.ComboBox2
.Enabled = True
.Value = vbNullString
End With
With Me.ComboBox3
.Enabled = False
.Value = vbNullString
End With
With Me.ComboBox4
.Enabled = False
.Value = vbNullString
End With
End Sub

Private Sub ComboBox2_Change()
a = Sheets("sheet1").Range("table1").Value
With CreateObject("scripting.dictionary")
For i = 1 To UBound(a, 1)
If a(i, 3) = Me.ComboBox2 And Not .Exists(a(i, 4)) Then .Add a(i, 4), a(i, 4) & "_content"
Next
Me.ComboBox3.List = Application.Transpose(.Keys)
End With
With Me.ComboBox3
.Enabled = True
.Value = vbNullString
End With
End Sub

Private Sub ComboBox3_Change()
a = Sheets("sheet1").Range("table1").Value
With CreateObject("scripting.dictionary")
For i = 1 To UBound(a, 1)
If Me.ComboBox3 = vbNullString Then Exit Sub
If a(i, 4) = CDate(Me.ComboBox3) And Not .Exists(a(i, 1)) Then .Add a(i, 1), a(i, 1) & "_content"
Next
Me.ComboBox4.List = Application.Transpose(.Keys)
End With
With Me.ComboBox4
.Enabled = True
.Value = vbNullString
End With
End Sub

Private Sub ComboBox4_Change()

End Sub

Private Sub UserForm_Initialize()
a = Sheets("sheet1").Range("table1").Value
With CreateObject("scripting.dictionary")
For i = 2 To UBound(a, 1)
If Not .Exists(a(i, 2)) Then .Add a(i, 2), a(i, 2) & "_content"
Next
Me.ComboBox1.List = Application.Transpose(.Keys)
End With
Me.ComboBox2.Enabled = False
Me.ComboBox3.Enabled = False
Me.ComboBox4.Enabled = False
End Sub[/VBA]

Any help would be very much appreciated

Thanks for the reply, currently getting an error type mismatch on the following line under the combo box 2 sub

[VBA]
With Me.ComboBox3.List = Application.Transpose(.Keys)
[/VBA]

I get that this is due to the date format of the field, is there any sort of work around for this?

Quote from KjBox

Your second request is for something that bears no resemblance to the thread title, please ask that in a separate thread with an appropriate title.

Will do, sorry, a bit of a newbie

Never mind. Solved!

Thank you so much KjBox for your assistance. Much appreciated.

Will create a thread re my other query