Get monday of current week based on userform input - vba

Question

I am very new to VBA, so please bear with me. I have a userform that is going to eventually create a 2 or 6 week schedule look ahead. The userform has a textbox which automatically populates the Monday of the current week as the lookahead start date. If the user inputs a date, it will use that date as the lookahead start date instead.
The part I can't seem to figure out, is the formula so that when the user inputs a date, it calculates the Monday of that week.
The code:
Private Sub UserForm_Initialize()
'Inserts date of Monday this week into "Start Date" field in UserForm
LookAheadDate1.Value = Date - Weekday(Date) + 2
End Sub
Private Sub Generate_Click()
Dim StartDate As Date
Dim EndDate As Date
Dim ws As Worksheet
Dim addme As Long
Set ws = Worksheets("Projects")
addme = ws.Cells(Rows.Count, 1).End(xlUp).Offset(1, 0).Row
' Clears Look Ahead sheet - Row 5 and below
With Sheets("Look Ahead")
.Rows(5 & ":" & .Rows.Count).Delete
End With
'Force user to select either option button
If ((Me.OptionButton1.Value = 0) * (Me.OptionButton2.Value = 0)) Then
MsgBox "Please select 2 or 6 Week Look Ahead"
End If
'Force user to select either option button
If ((Me.OptionButton1.Value)) Then
ThisWorkbook.Worksheets("Look Ahead").Range("E6").Value = "2 Week Look Ahead"
End If
If ((Me.OptionButton2.Value)) Then
ThisWorkbook.Worksheets("Look Ahead").Range("E6").Value = "6 Week Look Ahead"
End If
' Set StartDate Variable - If Start Date field value is blank, use this weeks start date, otherwise use start date field value
If IsNull(Me.LookAheadDate1.Value) Or Me.LookAheadDate1.Value = "" Then
StartDate = Date
Else
StartDate = LookAheadDate1.Value
End If
' Option buttons / Code to create end date for 2 or 6 week look ahead
Dim res As Date
If OptionButton1.Value Then
EndDate = StartDate - Weekday(Date) + 16
ElseIf OptionButton2.Value Then
EndDate = StartDate - Weekday(Date) + 44
End If
'Write Look Ahead date range in cell "E7"
ThisWorkbook.Worksheets("Look Ahead").Range("E7").Value = StartDate - Weekday(Date) + 2 & " to " & EndDate
'Clear all fields in UserForm
Dim oneControl As Object
For Each oneControl In ProjectData.Controls
Select Case TypeName(oneControl)
Case "TextBox"
oneControl.Text = vbNullString
Case "CheckBox"
oneControl.Value = False
End Select
Next oneControl
'Close UserForm.
Unload Me
End Sub
Private Sub ToggleButton1_Click()
End Sub
Private Sub UserForm_Click()
End Sub
Private Sub LookAheadDate1_Change()
End Sub
Private Sub Cancel_Click()
'Close UserForm if "Cancel" Button is pressed
Unload Me
End Sub
'Checks for entry of valid date
Private Sub LookAheadDate1_Exit(ByVal Cancel As MSForms.ReturnBoolean)
If LookAheadDate1 = vbNullString Then Exit Sub
If IsDate(LookAheadDate1) Then
LookAheadDate1 = Format(LookAheadDate1, "Short Date")
Else
MsgBox "Please Enter Valid Date"
Cancel = True
End If
End Sub
Private Sub UserForm_QueryClose(Cancel As Integer, CloseMode As Integer)
'If the user clicks the "X" to close the UserForm, then cancel
If CloseMode = 0 Then Cancel_Click
End Sub

Answer 1

If I understand your question about the date correctly, you want to edit this block of your code:
If IsNull(Me.LookAheadDate1.Value) Or Me.LookAheadDate1.Value = "" Then
StartDate = Date ' <--- this is where you want Monday, right?
Else
StartDate = LookAheadDate1.Value
End If
If so, replace the marked line with
StartDate = Date - Application.WorksheetFunction.Weekday(Date,3)
to get the date of Monday of this week as the StartDate.
Date returns the current date (similar to Now, but without the time part)
The use of Weekday (=WEEKDAY()) to get Monday is from this answer by Paul
Edit
In the Else branch:
Dim enteredDate as Date
enteredDate = CDate(LookAheadDate1.Value)
StartDate = enteredDate - Application.WorksheetFunction.Weekday(enteredDate,3)
CDate converts from text to date according to the current locale. You may need to parse the date text manually if you need a more sophisticated conversion.
I believe LookAheadDate1 is a text box because I see you are giving it a value using Format(..., "Short Date"). If it is a date/time picker, you may not need the CDate call.

Answer 2

I got it working. I added a calendar date picker to input the date into the textbox. Thanks for the help!