无法将类型“System.Data.DataSet”隐式转换为“System.DateTime”

Question

I am trying to get system date through this method but is showing error saying :

Cannot implicitly convert type 'System.Data.DataSet' to 'System.DateTime'

Below is the method I am using. Any suggestions are appreciated. As why is this happening and how can I resolve it?

public DateTime GetLocalTime()
        {
            OracleBridge ob = new OracleBridge(_connStr);
            string sqlQuery = "select sysdate from dual";

            DateTime dt = new DateTime();
            try
            {

                dt = Convert.ToDateTime(ob.ExecuteScalar(sqlQuery, CommandType.Text));    //this line is giving error

            }
            catch (OracleException ex)
            {
                throw ex;
            }

            return dt;
        }

Answer 1

You cannot convert, as the exception says, a DataSet type to a DateTime .

dt = ob.ExecuteQuery(sqlQuery, CommandType.Text);

That line is wrong. If you are expecting a only row result with a DateTime value, then you have to use the ExecuteScalar method and cast the result as DateTime:

dt = Convert.ToDateTime(yourOracleConnection.ExecuteScalar(sqlQuery, CommandType.Text)); //I assume you are using ADO.NET Library

If you are not expecting that result, you have to access to the specific row you are looking for, and then get the value as this:

dt = Convert.ToDateTime(ob.ExecuteQuery(sqlQuery, CommandType.Text).Tables[0].Rows[0]["YourColumnName"]); //You´ll have to check out where is the value you want and replace on the Rows[0]

Answer 2

If it is just one value that you are trying to retrieve then use ExecuteScalar method which will return an object.Convert it to datetime

    public DateTime GetLocalTime()
    {
        OracleBridge ob = new OracleBridge(_connStr);
        string sqlQuery = "select distinct sysdate from dual";

        DateTime dt = new DateTime();
        try
        {
            dt = Convert.ToDateTime(ob.ExecuteScalar(sqlQuery, CommandType.Text));
        }
        catch (OracleException ex)
        {
            throw ex;
        }

        return dt;
    }

Answer 3

Answers provided already should be sufficant, in terms of syntax, if you throw the exception further all you actually need is

catch (OracleException)
{
   throw;
}