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Clearing a Date filed in an Access DB ?

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David (VIP)

Hi,

I am using Webmatrix, and I have a Date field in an Access database that I
would like to let the user clear.

However, when the filed is cleared on a web form, and the values are
submitted, there is an error to the effect of:

System.InvalidCastException: Cast from string "" to type 'Date' is not valid

Any ideas?

Thanks, David

Reply to this message...

Cor Ligthert

David,

You can try when your code is vbnet = dbnull.value .

Cor

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David (VIP)

Thanks!

Here is the syntax I used: (I suspect an Iif() would have helped a bit..)

If airframe_date <> "" Then

Dim new_airframe_date As Date = CDate(airframe_date)

Dim dbParam_airframe_date As System.Data.IDataParameter = New
System.Data.OleDb.OleDbParameter
dbParam_airframe_date.ParameterName = "@airframe_date"
dbParam_airframe_date.Value = new_airframe_date
dbParam_airframe_date.DbType = System.Data.DbType.DateTime
dbCommand.Parameters.Add(dbParam_airframe_date)

Else

Dim new_airframe_date As Dbnull

Dim dbParam_airframe_date As System.Data.IDataParameter = New
System.Data.OleDb.OleDbParameter
dbParam_airframe_date.ParameterName = "@airframe_date"
dbParam_airframe_date.Value = new_airframe_date.value
dbParam_airframe_date.DbType = System.Data.DbType.DateTime
dbCommand.Parameters.Add(dbParam_airframe_date)

End IF

"Cor Ligthert" wrote:

[Original message clipped]

Reply to this message...

Cor Ligthert

David,

It is some guesing however probably are you trying to do something (as this
typed in this message so not checked and assuming you are using a SQL update
command) to do this.
\\\
If airframe_date = "" Then
Dim dbParam_airframe_date As System.Data.IDataParameter = New
System.Data.OleDb.OleDbParameter
dbParam_airframe_date.ParameterName = "@airframe_date"
dbParam_airframe_date.DbType = System.Data.DbType.DateTime
dbParam_airframe_date.Value = dbnull.value
dbCommand.Parameters.Add(dbParam_airframe_date)
End if
///

Maybe you can try it, I am looking almost in the dark you know.

Cor

Reply to this message...

	System.Data.DbType
	System.Data.IDataParameter
	System.Data.OleDb.OleDbParameter
	System.InvalidCastException

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