How do i...how best to indicate in a windows form application that there is "no value" in the date field?

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Visual Studio -Visual Basic - Windows Form.
ODBC connection to Sql server(10.50) dbase.

Database date Cloumn
General settings
- Data type = date.
- Allow Nulls = Yes.

How best to indicate in the Windows Form that there is "No value" in the date field?

Should i code to clear( set to null ) the value in the database? (if Possbile)?

or

Should i code to present an Null value or defauot value as "No value" ?

What I have tried:

I have cleared dates in a Datagridview on my windows from and "1900-01-01" is saved to the database date cloumn.
Not sure if this is the App, ODBC conenction or the Server providing this ?

Also
Datetimepicker : if null , How best to indicate in the Windows Form that there is "No value" in the date field.

Posted 10-Apr-19 17:56pm

Member 14138885

Updated 10-Apr-19 20:10pm

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Maciej Los · Answer 1 · 2019-04-10T20:10:00

Seems you're looking for DBNull.Value[^]

VB

If DbNUll.Value.Equals(DataBaseValue) Then
    'set default value
End If

or:

VB

DataBaseValue = IIf(Not DbNUll.Value.Equals(DataBaseValue), DataBaseValue, New DateTime(1900, 1, 1))

Note: DataBaseValue is a variable/field you want to check for null.

OriginalGriff · Answer 2 · 2019-04-10T19:59:00

Solution 1

You could use the DateTimePicker.Checked Property (System.Windows.Forms) | Microsoft Docs[^]
Other than that, you'd probably have to derive a control from the DateTimePicker and override OnPaint to display a message or similar. Shouldn't be difficult, but I haven't needed to do it myself.

Posted 10-Apr-19 19:59pm

OriginalGriff