VBA - Data validation empty cell - vba

Question

I created named ranges in excel, naming of range is based on key values on the sheet2.
Now I created dropdown list on another sheet1, with formula usage - INDIRECT, based again on key, on sheet1 . How I can add blank/special symbol to dropdown list? I cant add empty cell between the sorted items on sheet.
Sheet2:
I have 2 named ranges based on MAT/AE columns, first one is range of C2:C4, and the next one is C5:C6.
And there I have Sheet1, I using data validation , concatenating MAT1&AE11 using formula INDIRECT and i have values based on ranges from Sheet2.
SO my question is, how to add blank/special character to this list?
Code for ranges :
Sub Start()
lf_index_row = 1
lf_name_space_row = 2
gf_namespace = ""
Do
lf_index_row = lf_index_row + 1
lf_material = Sheets(gc_data).Cells(lf_index_row, 1)
lf_location = Sheets(gc_data).Cells(lf_index_row, 2)
gf_new_namespace = "X" & lf_material & lf_location
If gf_new_namespace = "X" Then
If gf_namespace = "" Then
End
Else
'create namespace
Set lf_range = Range(Cells(lf_start_number, 3), Cells(lf_end_number, 3))
lf_range.Select
Range(Cells(lf_start_number, 3), Cells(lf_end_number, 3)).Select
ActiveWorkbook.Names.Add Name:=gf_namespace, RefersTo:=lf_range
End
End If
End If
If gf_namespace <> gf_new_namespace Then
If gf_namespace = "" Then
'initialize newnamespace
gf_namespace = gf_new_namespace
lf_start_number = lf_index_row
lf_end_number = lf_index_row
Else
'create namespace
Set lf_range = Range(Cells(lf_start_number, 3), Cells(lf_end_number, 3))
lf_range.Select
Range(Cells(lf_start_number, 3), Cells(lf_end_number, 3)).Select
ActiveWorkbook.Names.Add Name:=gf_namespace, RefersTo:=lf_range
'initialize newnamespace
gf_namespace = gf_new_namespace
lf_start_number = lf_index_row
lf_end_number = lf_index_row
End If
Else
lf_end_number = lf_index_row
End If
Loop
End Sub
Indirect formula :
Definition of first named range :

Answer 1

If the list is in Range("A1:A10") this is how to achieve a validation list with only one empty position:
with the following code:
Sub TestMe()
Dim list1 As Range
Dim validationFormula As String
Set list1 = Range("A1:A10")
Dim myCell As Range
For Each myCell In list1
If Not IsEmpty(myCell) Then
validationFormula = validationFormula & myCell.Value2 & ","
End If
Next
validationFormula = validationFormula & Chr(160)
With Range("B5").Validation
.Delete
.Add Type:=xlValidateList, Operator:=xlBetween, Formula1:=validationFormula
.IgnoreBlank = False
.InCellDropdown = True
End With
End Sub
What is the idea of the code? The validation string is made in the validationFormula, through concatenating all the cells that are Not IsEmpty(). Once the validationFormula is ready, Chr(160) is added to it, to make sure that we have the empty cell available as well.
It can be added even like this: validationFormula = Chr(160) & "," & validationFormula, if you need to have it at the first position:
Once the validationFormula string is prepared, we can allow ourself to write .IgnoreBlank = True, as far as there is only one blank in the list - the one we need.
Credits to this guy here, for the looping idea - https://superuser.com/questions/1254754/data-validation-from-2-lists-excel-2010

Answer 2

Check if cell with row-value = 3 and column-value = 4 is blank with the following:
Set objExcel = CreateObject("Excel.Application")
Set excelInput = objExcel.Workbooks.Open("myfile")
If excelInput.Sheets("Sheet1").Cells(3, 4) <> vbNullString Then
'do the thing
End If
The above code is VBScript but it should work. If not, its almost identical in VBA.