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I'm getting error converting parameters from DateTime to Byte[]. The idea is to show data between 2 specified dates that are entered via controls and displayed on GridView, and using a stored procedure to access data. I don't understand the error, but I'm guessing that all the data is put in an Array and passed on to stored procedure:

string sDateBegin = Request.Form["fromDate"];
DateTime dtDateBegin = Convert.ToDateTime(sDateBegin);
SqlParameter prmDateBegin = new SqlParameter("datebegin", SqlDbType.Timestamp);
prmDateBegin.Value = dtDateBegin;
cmdProc.Parameters.Add(prmDateBegin);

//same code for DateEnd

// data table
DataTable dataTable = new DataTable();

AGridView.DataSourceID = null;

// data adapter
SqlDataAdapter dataAdapter = new SqlDataAdapter(cmdProc);
AGridView.DataSource = dataTable;

//fill datatable
dataAdapter.Fill(dataTable);
malvina
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  • Hello malvina, welcome to StackOverflow. We're having some problems seeing exactly what is going on here, because we're missing some information (such as the programming language you are using, and what database engine and/or frameworks you are using). Please help us help you, by filling in those blanks. – Timothy Groote Feb 20 '12 at 16:23
  • Thanks for reply. I'm using .Net framework, C# and MS SQL Server 2005. – malvina Feb 20 '12 at 16:28
  • Does the error occur on `DateTime dtDateBegin = Convert.ToDateTime(sDateBegin);` ? if so, this could maybe be resolved by using `DateTime.Parse(string input)` (see http://msdn.microsoft.com/en-us/library/1k1skd40.aspx ) The reason i can't be sure yet, is that it is hard to tell what the stored procedure and gridview controls you mentioned are doing ;) – Timothy Groote Feb 21 '12 at 09:12
  • Thanx Timothy, that actually worked! thanks a million :) – malvina Feb 21 '12 at 10:19
  • You're welcome. I have added an answer that should clarify what was going on :) – Timothy Groote Feb 21 '12 at 10:52

2 Answers2

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You've defined the SqlParameter as a Timestamp data type (which is a byte array) rather than a DateTime. Given you're representing a date range it sounds like you should change the parameter data type to DateTime.

kaj
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    +1. And another one not reading the documentation what Timestamp means. I love that. This question is SO suitable in inteviwes for senior people - just a side querstion, get the (wrong answer), take the resume and put it where it belongs - garbage bin. Timestamp data type has nothing to do with timestamps ;) – TomTom Feb 21 '12 at 09:40
  • Thanks, unfortunately, I have had tried this already and it didn't make any difference, the error was the same. – malvina Feb 21 '12 at 10:20
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The error occurred because Convert.ToDateTime tries to do an implicit conversion from any object to a DateTime. The object coming from the control is a string, but not one that could be cast to a DateTime object. It is in fact a date and time represented by a string.

The correct way to construct a DateTime object is by parsing the string with

DateTime.Parse(string input)
Timothy Groote
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