Conversion failed when converting datetime from character string

Question

I am developing a C# VS 2008 / SQL Server 2005 Express website application. I have tried some of the fixes for this problem but my call stack differs from others. And these fixes did not fix my problem. What steps can I take to troubleshoot this?

Here is my error:

System.Data.SqlClient.SqlException was caught
  Message="Conversion failed when converting datetime from character string."
  Source=".Net SqlClient Data Provider"
  ErrorCode=-2146232060

  LineNumber=10
  Number=241
  Procedure="AppendDataCT"
  Server="\\\\.\\pipe\\772EF469-84F1-43\\tsql\\query"
  State=1
  StackTrace:
       at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
       at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
       at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)
       at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
       at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
       at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async)
       at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result)
       at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe)
       at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
       at ADONET_namespace.ADONET_methods.AppendDataCT(DataTable dt, Dictionary`2 dic) in c:\Documents and Settings\Admin\My Documents\Visual Studio 2008\WebSites\Jerry\App_Code\ADONET methods.cs:line 102

And here is the related code. When I debugged this code, "dic" only looped through the 3 column names, but did not look into row values which are stored in "dt", the Data Table.

public static string AppendDataCT(DataTable dt, Dictionary<string, string> dic)
{
    if (dic.Count != 3)
        throw new ArgumentOutOfRangeException("dic can only have 3 parameters");

    string connString = ConfigurationManager.ConnectionStrings["AW3_string"].ConnectionString;
    string errorMsg;

    try
    {               
        using (SqlConnection conn2 = new SqlConnection(connString))
        {
            using (SqlCommand cmd = conn2.CreateCommand())
            {
                cmd.CommandText = "dbo.AppendDataCT";
                cmd.CommandType = CommandType.StoredProcedure;
                cmd.Connection = conn2;
                foreach (string s in dic.Keys)
                {
                    SqlParameter p = cmd.Parameters.AddWithValue(s, dic[s]);
                    p.SqlDbType = SqlDbType.VarChar;
                }

                conn2.Open();
                cmd.ExecuteNonQuery();
                conn2.Close();
                errorMsg = "The Person.ContactType table was successfully updated!";
            }
        }
    }

Here is my SQL stored proc:

ALTER PROCEDURE [dbo].[AppendDataCT] 
@col1 VARCHAR(50), 
@col2 VARCHAR(50),
@col3 VARCHAR(50)
AS
BEGIN
SET NOCOUNT ON;
DECLARE @TEMP DATETIME
SET @TEMP = (SELECT CONVERT (DATETIME, @col3))

INSERT INTO Person.ContactType (Name, ModifiedDate)
VALUES( @col2, @TEMP)
END

The input file has 3 columns. The first two are varchars, but the 3rd one is also varchar I think, but it's represented as "3/11/2010". In this input file, a sample row looks like: "Benjamin|breakfast|3/11/2010". And I am trying to convert this date field from a string to a datetime here in my SP. Am I going about it the wrong way?

DataRow: col1|col2|col3 11|A2|1/10/1978 12|b2|2/10/1978 13|c2|3/10/1978 14|d2|4/10/1978

Answer 1

Problem is in stored procedure, I think. May be one of input parameters is DateTime, but you wrote VarChar to this parameter.

UPDATE:

As I can see you don't use DataTable dt in your method AppendDataCT.

You wrote that dic contains values [0]:[col1, col1] [1]:[col2, col2] [2]:[col3, col3]. But it's wrong values... your code is

SqlParameter p = cmd.Parameters.AddWithValue(s, dic[s]);

Then you send to col3 value = col3, as I understand.

May be you wanted to write

SqlParameter p = cmd.Parameters.AddWithValue(s, dt[s]);

or something like this...

Answer 2

I think Belousov Pavel is correct. Inside your foreach you assign each dictionary item as a parameter. Each of those parameters are defined as being VarChar. With the information provided it is logical to assume the problem is in the stored procedure.

Can you either post the code of the stored procedure or try and recreate the error inside SQL Management Studio by executing the stored procedure there.

UPDATE...

After looking at your stored procedure the code looks correct. I was able to generate the error message you are getting using the following sql code.

declare @col3 varchar(50)

set @col3 = '|3/11/2010'

declare @temp datetime

set @temp = (select convert(datetime,@col3))

Note that the value of @col3 starts with a pipe character. If you remove the pipe character it works correctly.

I would look closer at the values in the dictionary you are getting you parameter values from. There may be an issue with the way you parsed the data.

UPDATE 2

The code below is not confirmed to work but I think I see what you are trying to do. I assume the DataTable you are passing in has data like this:

col1|col2|col3 11|A2|1/10/1978 12|b2|2/10/1978 13|c2|3/10/1978 14|d2|4/10/1978

If this is the case we don't need the dictionary that was passed in originally. I can also assume that you want the stored procedure to be executed once for each row in the DataTable. The below method is similar to what you where doing although it runs the stored procedure for each row.

What I am not sure from you explanation is if the first row of the DataTable contains the names of the columns, if not no worries then. Hope this makes sense, leave more comments if you have questions.

    public static string TestMethod(DataTable dt)
    {
        string connString = "";
        string errorMsg = string.Empty;

        try
        {
            //loop through each row of the datatable. Not sure if the column names is a row.
            foreach (DataRow row in dt.Rows)
            {
                using (SqlConnection conn2 = new SqlConnection(connString))
                {
                    using (SqlCommand cmd = conn2.CreateCommand())
                    {
                        cmd.CommandText = "dbo.AppendDataCT";
                        cmd.CommandType = CommandType.StoredProcedure;
                        cmd.Connection = conn2;

                        cmd.Parameters.Add(new SqlParameter() { ParameterName = "@col1", SqlDbType = SqlDbType.VarChar, Value = row[0] });
                        cmd.Parameters.Add(new SqlParameter() { ParameterName = "@col2", SqlDbType = SqlDbType.VarChar, Value = row[1] });
                        cmd.Parameters.Add(new SqlParameter() { ParameterName = "@col3", SqlDbType = SqlDbType.VarChar, Value = row[2] });

                        conn2.Open();
                        cmd.ExecuteNonQuery();
                        conn2.Close();
                    }
                }                
            }
            errorMsg = "The Person.ContactType table was successfully updated!";
        }
        catch
        {
        }

        return errorMsg;
    }

Answer 3

Well, if you do this:

SqlParameter p = cmd.Parameters.AddWithValue(s, dic[s]);
p.SqlDbType = SqlDbType.VarChar;

all your parameters will be of type VARCHAR. This might sound smart at first - it's not.

If you pass dates as varchar, you start getting into the messy business of date/time string formats - unless you always use the ISO-8601 format YYYYMMDD which works on any SQL Server installation, and with any locale / language / date setting. Anything else becomes a gamble. Not the whole world uses the MM/DD/YYYY format as in the US, and depending on your SQL Server's language or date format settings, your date might not be recognized, or even misinterpreted. Just don't do it - it's a mess.

Plus, really - if you have a date/time in your C# code - I would strongly recommend you pass that as a SqlDbType.DateTime to your SQL Server stored proc. You're just gonna save yourself endless hours of debugging and messy conversions and stuf.......

Answer 4

You need to loop through the rows of the DataTable to get the data - you're adding the values of dic (your column names for month, day, year??) as SqlParameters..... This is what I'm assuming because the question is pretty scattered....

Note: Not completely functioning code -

foreach(DataRow dr in dt.Rows)
{
    DateTime date = new DateTime();

    foreach(string s in dic.Keys)
    {  
        switch(dic[s])
        {
            case "Month":
                date.Month = dr[dic[s]];
                break;
            case "Day":
                date.Day = dr[dic[s]];
                break;
            case "Year":
                date.Year = dr[dic[s]];
                break;
        }

    }

    // If valid date
    SqlParameter p = cmd.Parameters.AddWithValue("Date", date);
    p.SqlDbType = SqlDbType.DateTime;      


}

UPDATE: You will need to handle your own data validation - otherwise, here you go

    using (SqlConnection conn2 = new SqlConnection(connString))
    {
        using (SqlCommand cmd = conn2.CreateCommand())
        {
            conn2.Open();               


            foreach(DataRow dr in dt.Rows)
            {
                 SqlParameter col1 = cmd.Parameters.AddWithValue(dic[0], dr[0].ToString());
                 SqlParameter col2 = cmd.Parameters.AddWithValue(dic[1], dr[1].ToString());
                 SqlParameter col3 = cmd.Parameters.AddWithValue(dic[2], Convert.ToDateTime(dr[2]));

                 cmd.ExecuteNonQuery();

            }

            conn2.Close();
        }
   }