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bubberz
Constraint Violating Yak Guru
289 Posts |
 Posted - 2005-09-12 : 18:25:05
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| When I run the following code I get:Cast from type 'DBNull' to type 'Date' is not valid.The datatype for the field is smalldatetime.I can run it fine from SQL ServerDim strSQL As String strSQL = "SELECT MIN(ESDate) AS MinDate, MAX(EFDate) AS MaxDate FROM P3ActWBS WHERE " strSQL &= "WBSNumber = '" & strWBSN & "'" Dim cmd2 As New SqlCommand(strSQL, sCon1) Dim DR2 As SqlDataReader = cmd2.ExecuteReader() DR2.Read() If DR2.HasRows = True Then Dim strMinDate As Date = DR2(0) Dim strMaxDate As Date = DR2(1) DR2.Close() DR2 = Nothing |
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jsmith8858
Dr. Cross Join
7423 Posts |
Posted - 2005-09-13 : 08:49:22
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| As the error message says, the "Date" datatype in .NET cannot handle nulls. You need to explicitly handle the situation in which DR2(0) or DR2(1) returns DBNull and set your variables to valid dates.. i.e., you can use 1/1/1900 or something like that. Also, you could create your own datatype that allows for Nulls. I believe vs 2005 implements nullable data types.Finally -- why the heck have you prefixed your date variables with "str" ? It's bad enough, in general, to use datatype prefixes in variables in modern code, but even worse when you use the WRONG prefix ! Your code is very, very inconsistent in your naming conventions. |
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Min() / Max() date cast error from type DBNull