weekdayname - Datetime - VB6Parse Library Reference

VB6 WeekdayName Function

The WeekdayName function returns a string indicating the specified day of the week.

Syntax

WeekdayName(weekday[, abbreviate[, firstdayofweek]])

Parameters

weekday: Required. The numeric designation for the day of the week. Numeric value of each day depends on the firstdayofweek setting.
abbreviate: Optional. Boolean value that indicates if the weekday name is to be abbreviated. If omitted, the default is False (not abbreviated).
firstdayofweek: Optional. Numeric value indicating the first day of the week. See Settings section for values.

`FirstDayOfWeek` Constants

vbUseSystemDayOfWeek (0): Use National Language Support (NLS) API setting
vbSunday (1): Sunday (default)
vbMonday (2): Monday
vbTuesday (3): Tuesday
vbWednesday (4): Wednesday
vbThursday (5): Thursday
vbFriday (6): Friday
vbSaturday (7): Saturday

Returns

Returns a String containing the name of the specified day of the week. The string is localized based on the system's regional settings.

Remarks

The WeekdayName function provides localized day names:

Localization: Returns day names according to system locale (e.g., "Monday" in English, "Lundi" in French)
Abbreviation: When abbreviate is True, returns shortened form (e.g., "Mon" instead of "Monday")
Weekday parameter: Numeric value from 1 to 7
Default first day: Sunday (vbSunday = 1) if firstdayofweek not specified
Consistency with Weekday: Use same firstdayofweek value as Weekday function for consistency
System locale: Output language depends on Windows regional settings
Case sensitivity: Returned string typically has proper capitalization
Abbreviation length: Typically 3 characters in English, varies by locale

Understanding Weekday Parameter

The weekday parameter's meaning depends on firstdayofweek: - If firstdayofweek is vbSunday (default): 1=Sunday, 2=Monday, 3=Tuesday, etc. - If firstdayofweek is vbMonday: 1=Monday, 2=Tuesday, 3=Wednesday, etc. - The number always refers to the position in the week, starting from the specified first day

Abbreviation Examples (English locale)

Full: "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"
Abbreviated: "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"

Combining with Weekday Function

' Get the name of today's day
dayName = WeekdayName(Weekday(Date))

Typical Uses

Display Day Names: Show user-friendly day names in UI
Report Headers: Label columns or sections with day names
Calendar Applications: Display calendar grid headers
Localized Applications: Provide day names in user's language
Schedule Display: Show schedule with day names
Date Formatting: Create custom date format strings
Dropdown Lists: Populate day selection dropdowns
Log Files: Human-readable date information in logs

Basic Examples

Example 1: Get Today's Day Name

Sub ShowTodayName()
Dim todayName As String
todayName = WeekdayName(Weekday(Date))
MsgBox "Today is " & todayName
End Sub

Example 2: Display All Day Names

Sub ListAllDays()
Dim i As Integer
For i = 1 To 7
Debug.Print WeekdayName(i)
Next i
End Sub

Example 3: Abbreviated Day Names

Function GetAbbreviatedDayName(dayNumber As Integer) As String
GetAbbreviatedDayName = WeekdayName(dayNumber, True)
End Function

' Usage:
Debug.Print GetAbbreviatedDayName(1) ' Prints "Sun" (if vbSunday is first day)

Example 4: Create Calendar Header

Function CreateCalendarHeader(Optional abbreviated As Boolean = True) As String
Dim i As Integer
Dim header As String

header = ""
For i = 1 To 7
header = header & WeekdayName(i, abbreviated, vbSunday) & vbTab
Next i

CreateCalendarHeader = header
End Function

Common Patterns

Pattern 1: Format Date with Day Name

Function FormatDateWithDayName(dt As Date) As String
FormatDateWithDayName = WeekdayName(Weekday(dt)) & ", " & Format$(dt, "mmmm d, yyyy")
End Function

Pattern 2: Get All Day Names Array

Function GetDayNamesArray(Optional abbreviated As Boolean = False) As String()
Dim days(1 To 7) As String
Dim i As Integer

For i = 1 To 7
days(i) = WeekdayName(i, abbreviated)
Next i

GetDayNamesArray = days
End Function

Pattern 3: ISO Week Day Names (Monday First)

Function GetISODayName(dayNumber As Integer, Optional abbreviated As Boolean = False) As String
GetISODayName = WeekdayName(dayNumber, abbreviated, vbMonday)
End Function

Pattern 4: Populate `ComboBox` with Days

Sub PopulateDayCombo(combo As ComboBox)
Dim i As Integer
combo.Clear
For i = 1 To 7
combo.AddItem WeekdayName(i)
Next i
End Sub

Pattern 5: Get Day Initials

Function GetDayInitial(dayNumber As Integer) As String
GetDayInitial = Left$(WeekdayName(dayNumber, True), 1)
End Function

Pattern 6: Create Week Schedule Header

Function CreateWeekSchedule() As String
Dim i As Integer
Dim schedule As String

schedule = "Week Schedule:" & vbCrLf
For i = 1 To 7
schedule = schedule & WeekdayName(i) & ": _____" & vbCrLf
Next i

CreateWeekSchedule = schedule
End Function

Pattern 7: Format Event Description

Function FormatEventDescription(eventDate As Date, eventName As String) As String
FormatEventDescription = eventName & " on " & _
WeekdayName(Weekday(eventDate)) & ", " & _
Format$(eventDate, "mmmm d")
End Function

Pattern 8: Get Weekday vs Weekend Label

Function GetDayTypeLabel(dt As Date) As String
Dim dayNum As Integer
dayNum = Weekday(dt)

If dayNum = vbSaturday Or dayNum = vbSunday Then
GetDayTypeLabel = WeekdayName(dayNum) & " (Weekend)"
Else
GetDayTypeLabel = WeekdayName(dayNum) & " (Weekday)"
End If
End Function

Pattern 9: Create Pivot Headers

Function CreatePivotDayHeaders() As Variant
Dim headers(1 To 7) As String
Dim i As Integer

For i = 1 To 7
headers(i) = WeekdayName(i, True, vbMonday)
Next i

CreatePivotDayHeaders = headers
End Function

Pattern 10: Conditional Day Name Display

Function GetDisplayDayName(dt As Date, useAbbreviation As Boolean) As String
GetDisplayDayName = WeekdayName(Weekday(dt), useAbbreviation)
End Function

Advanced Usage

Example 1: Calendar Header Generator Class

' Class: CalendarHeaderGenerator
' Generates calendar headers with configurable options
Option Explicit

Private m_FirstDayOfWeek As VbDayOfWeek
Private m_Abbreviated As Boolean
Private m_Separator As String

Public Sub Initialize(Optional firstDay As VbDayOfWeek = vbSunday, _
Optional abbreviated As Boolean = True, _
Optional separator As String = " ")
m_FirstDayOfWeek = firstDay
m_Abbreviated = abbreviated
m_Separator = separator
End Sub

Public Function GenerateHeader() As String
Dim i As Integer
Dim header As String

header = ""
For i = 1 To 7
If i > 1 Then header = header & m_Separator
header = header & WeekdayName(i, m_Abbreviated, m_FirstDayOfWeek)
Next i

GenerateHeader = header
End Function

Public Function GenerateHeaderArray() As String()
Dim headers(1 To 7) As String
Dim i As Integer

For i = 1 To 7
headers(i) = WeekdayName(i, m_Abbreviated, m_FirstDayOfWeek)
Next i

GenerateHeaderArray = headers
End Function

Public Function GetDayName(dayNumber As Integer) As String
If dayNumber < 1 Or dayNumber > 7 Then
Err.Raise 5, , "Day number must be between 1 and 7"
End If
GetDayName = WeekdayName(dayNumber, m_Abbreviated, m_FirstDayOfWeek)
End Function

Example 2: Date Formatter Module

' Module: DateFormatter
' Advanced date formatting with day names
Option Explicit

Public Function FormatLongDate(dt As Date) As String
FormatLongDate = WeekdayName(Weekday(dt)) & ", " & _
Format$(dt, "mmmm d, yyyy")
End Function

Public Function FormatShortDate(dt As Date) As String
FormatShortDate = WeekdayName(Weekday(dt), True) & " " & _
Format$(dt, "mm/dd/yyyy")
End Function

Public Function FormatScheduleDate(dt As Date) As String
FormatScheduleDate = WeekdayName(Weekday(dt), True) & ", " & _
Format$(dt, "mmm d")
End Function

Public Function FormatCalendarDate(dt As Date) As String
FormatCalendarDate = WeekdayName(Weekday(dt)) & vbCrLf & _
Format$(dt, "d")
End Function

Public Function GetDayWithOrdinal(dt As Date) As String
Dim dayNum As Integer
Dim suffix As String

dayNum = Day(dt)

Select Case dayNum
Case 1, 21, 31
suffix = "st"
Case 2, 22
suffix = "nd"
Case 3, 23
suffix = "rd"
Case Else
suffix = "th"
End Select

GetDayWithOrdinal = WeekdayName(Weekday(dt)) & ", " & _
MonthName(Month(dt)) & " " & dayNum & suffix
End Function

Example 3: Schedule Analyzer Class

' Class: ScheduleAnalyzer
' Analyzes schedules and provides day-based insights
Option Explicit

Public Function GetDayDistributionReport(dates() As Date) As String
Dim dayCounts(1 To 7) As Integer
Dim i As Long
Dim report As String
Dim dayNum As Integer

' Count occurrences
For i = LBound(dates) To UBound(dates)
dayNum = Weekday(dates(i))
dayCounts(dayNum) = dayCounts(dayNum) + 1
Next i

' Build report
report = "Day Distribution:" & vbCrLf
For i = 1 To 7
report = report & WeekdayName(i) & ": " & dayCounts(i) & vbCrLf
Next i

GetDayDistributionReport = report
End Function

Public Function GetMostCommonDay(dates() As Date) As String
Dim dayCounts(1 To 7) As Integer
Dim i As Long
Dim maxCount As Integer
Dim maxDay As Integer
Dim dayNum As Integer

For i = LBound(dates) To UBound(dates)
dayNum = Weekday(dates(i))
dayCounts(dayNum) = dayCounts(dayNum) + 1
Next i

maxCount = 0
maxDay = 1
For i = 1 To 7
If dayCounts(i) > maxCount Then
maxCount = dayCounts(i)
maxDay = i
End If
Next i

GetMostCommonDay = WeekdayName(maxDay)
End Function

Public Function CreateDaySummary(dates() As Date) As Collection
Dim summary As New Collection
Dim i As Integer

For i = 1 To 7
summary.Add 0, WeekdayName(i)
Next i

Dim dt As Variant
For Each dt In dates
Dim dayName As String
dayName = WeekdayName(Weekday(dt))
summary.Remove dayName
summary.Add summary(dayName) + 1, dayName
Next dt

Set CreateDaySummary = summary
End Function

Example 4: Localization Helper Module

' Module: LocalizationHelper
' Helps with localized day name handling
Option Explicit

Public Function GetLocalizedDayNames(Optional abbreviated As Boolean = False, _
Optional firstDay As VbDayOfWeek = vbSunday) As String()
Dim names(1 To 7) As String
Dim i As Integer

For i = 1 To 7
names(i) = WeekdayName(i, abbreviated, firstDay)
Next i

GetLocalizedDayNames = names
End Function

Public Function CreateDayNameLookup(Optional abbreviated As Boolean = False) As Collection
Dim lookup As New Collection
Dim i As Integer

For i = 1 To 7
lookup.Add WeekdayName(i, abbreviated), CStr(i)
Next i

Set CreateDayNameLookup = lookup
End Function

Public Function FindDayNumber(dayName As String) As Integer
Dim i As Integer

For i = 1 To 7
If UCase$(WeekdayName(i)) = UCase$(dayName) Then
FindDayNumber = i
Exit Function
End If
If UCase$(WeekdayName(i, True)) = UCase$(dayName) Then
FindDayNumber = i
Exit Function
End If
Next i

FindDayNumber = 0 ' Not found
End Function

Public Function IsDayNameValid(dayName As String) As Boolean
IsDayNameValid = (FindDayNumber(dayName) > 0)
End Function

Public Function NormalizeDayName(dayName As String) As String
Dim dayNum As Integer
dayNum = FindDayNumber(dayName)

If dayNum > 0 Then
NormalizeDayName = WeekdayName(dayNum)
Else
NormalizeDayName = ""
End If
End Function

Error Handling

The WeekdayName function can raise the following errors:

Error 5 (Invalid procedure call or argument): If weekday is less than 1 or greater than 7
Error 5 (Invalid procedure call or argument): If firstdayofweek is not between 0 and 7
Error 13 (Type mismatch): If arguments are not of correct type

Performance Notes

Very fast operation - simple lookup/formatting
Constant time O(1) complexity
No significant performance difference between abbreviated and full forms
Can be called repeatedly without performance concerns
Consider caching day name arrays if used frequently in loops

Best Practices

Use consistent firstdayofweek with Weekday function to avoid confusion
Cache day name arrays if populating lists or grids repeatedly
Handle localization - day names will differ based on system locale
Document expectations about which day is first in week
Use abbreviation parameter for space-constrained displays
Validate weekday range (1-7) before calling
Consider MonthName for consistent date formatting patterns
Test with different locales if application is internationalized
Use named constants (vbMonday, etc.) for clarity
Combine with Format$ for custom date displays

Comparison Table

Function	Purpose	Returns	Localized
`WeekdayName`	Get day name	String	Yes
`Weekday`	Get day number	Integer (1-7)	No
`MonthName`	Get month name	String	Yes
`Format$`	Format date	String	Partially

Platform Notes

Available in VB6, VBA, and VBScript
Behavior consistent across platforms
Output localized based on system regional settings
Abbreviation format varies by locale
English (US): "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
Other languages will return appropriate translations

Limitations

Cannot customize day name output (uses system locale)
Abbreviation length not configurable (determined by locale)
No way to get day name in specific language (uses system setting)
Cannot get day names for custom calendars (e.g., Hebrew, Islamic)
No built-in way to get single-letter day abbreviations
Cannot specify case (capitalization) of returned string