I have a ListBox populated by TextBoxes in a UserForm. Currently it will not update or save new data if any of the textboxes where numbers are expected are BLANK.. what is the way around this .. here is the code I am using for SAVING data to a sheet 
Private Sub cmd_Save_Click()
    
    Dim sh As Worksheet
        Set sh = ThisWorkbook.Worksheets("ANALYSISDB")
    Dim lr As Long
    lr = ThisWorkbook.Worksheets("ANALYSISDB").Range("A" & Rows.Count).End(xlUp).Row
    
    'Add data to sheet
        With sh
            .Cells(lr + 1, "A").Value = Me.txt_Name.Value
            .Cells(lr + 1, "B").Value = Me.cmb_Category.Value
            .Cells(lr + 1, "C").Value = Me.cmb_Phase.Value
            .Cells(lr + 1, "D").Value = CDec(Replace(Me.txt_Crest.Value, ",", Application.International(xlDecimalSeparator)))
            .Cells(lr + 1, "E").Value = CDec(Replace(Me.txt_GOC.Value, ",", Application.International(xlDecimalSeparator)))
            .Cells(lr + 1, "F").Value = CDec(Replace(Me.txt_HWC.Value, ",", Application.International(xlDecimalSeparator)))
            .Cells(lr + 1, "G").Value = CDec(Replace(Me.txt_OP.Value, ",", Application.International(xlDecimalSeparator)))
            .Cells(lr + 1, "H").Value = CDec(Replace(Me.txt_GasGrad.Value, ",", Application.International(xlDecimalSeparator)))
            .Cells(lr + 1, "I").Value = CDec(Replace(Me.txt_OilGrad.Value, ",", Application.International(xlDecimalSeparator)))
            .Cells(lr + 1, "J").Value = CDec(Replace(Me.txt_WaterGrad.Value, ",", Application.International(xlDecimalSeparator)))
            .Cells(lr + 1, "K").Value = Me.txt_RefWell.Value
            .Cells(lr + 1, "L").Value = Me.chbDisplay.Value
            .Cells(lr + 1, "M").Value = Me.chbLabel.Value
            .Cells(lr + 1, "N").Value = CDec(Replace(Me.txt_RC.Value, ",", Application.International(xlDecimalSeparator)))
            .Cells(lr + 1, "O").Value = CDec(Replace(Me.txt_FracGradValue.Value, ",", Application.International(xlDecimalSeparator)))
    
            
        End With
        
            
            Call Refresh_Data
            
            MsgBox "Data has been saved to the Database", vbInformation
            txt_Name.SetFocus
            
txt_Count.Value = ThisWorkbook.Worksheets("EXTRAS").Range("A42")
         
End Sub