Returning Multiple Result Sets from a SQL Stored Procedure for use in a C# Application.

With much frustration and trial and error I have recently discovered that I can not return all results of a multi-result set stored procedure using the generated fill method of a dataset. It appears that typed datasets are only allowed to return a single result set as per the dataset architecture. However, thankfully there is a workaround, if the dataset is a non-typed dataset then it is possible to access the result sets by means of the DataSet.Tables collection.

If you already have a stored procedure which returns multiple result sets then here is the code for accessing each result set that the dataset contains.


using System.Data;
using System.Data.SqlClient;

public DataSet GetDataFor(int param1, int param2)
      SqlConnection sqlConnection;
      dataSet = new DataSet();
      SqlDataAdapter sqlDataAdapter;

      sqlConnection = new SqlConnection(Properties.Settings.Default.AEORIONSMSConnectionString);

      sqlDataAdapter = new SqlDataAdapter([Replace with your sp name], sqlConnection);
      sqlDataAdapter.SelectCommand.CommandType = CommandType.StoredProcedure;

      sqlDataAdapter.SelectCommand.Parameters.AddWithValue("@param1", param1);
      sqlDataAdapter.SelectCommand.Parameters.AddWithValue("@param2", param2);


      return dataSet;

Using the returned DataSet:

void GetColumns()
     var dataSet = GetDataFor(1, 3);

     string[] columnNames1 = dataSet.Tables[0].Columns.Cast<DataColumn>().Select(x => x.ColumnName).ToArray();
     string[] columnNames2 = dataSet.Tables[1].Columns.Cast<DataColumn>().Select(x => x.ColumnName).ToArray();
     string[] columnNames3 = dataSet.Tables[2].Columns.Cast<DataColumn>().Select(x => x.ColumnName).ToArray();

How To Call Functions In a MATLAB Generated .NET DLL From C#

This Tutorial does not represent a practical use of  a MATLAB generated .NET DLL since it requires the installation and use of MATLAB and the MATLAB Compiler Runtime (MCR) for a scenario that could be easily handled by a more elegant algorithm such as the one discussed in my earlier post on RPN expression parsing. However, it does seek to demonstrate the principles behind developing an algorithm in MATLAB which could be then exported to a .NET component and reused in any managed language. MATLAB provides a fast prototyping environment which gives the programmer a vast array of tools which she can then use to design and test her algorithms. A subset of these functionalities are provided in the MCR which is basically an installable, free, headless version of MATLAB. Since the MCR is a MATLAB instance it requires the same amount of time for initial loading into memory and will also be as memory intensive as its GUI cousin.

That said,  MATLAB allows the packaging of its code into an encrypted Dll file which can then be executed by the MCR. In addition to .NET, MATLAB code can also be exported to C libraries , Java libraries or an executable file.

The first thing we will do is fire up MATLAB, we will access its computational engine through the use of  of  the eval  function which will return the result of a mathematical expression passed to it as a string.  There are the steps.

  1. Launch MATLAB
  2. Type edit in the MATLAB command window then press enter/return. 
  3. In the new window create the function as seen below then hit the save button.
    function result = calculator(input)
    result = eval(input);
  4. Click File->New->Deployment Project then type calculator in the name box.
  5. Select a location to save the project and .NET Assembly from the type drop down box.
  6. In the .NET Assembly window, under the build tab change the default name of the class to “demo” then drag and drop the calculator.m file unto the class to add it as a method of the class, then hit the compile button. This should create the calculator.dll which can be referenced from your c# application.
  7. Fire up Visual Studio and create a new C# Windows Forms Application, to this application add a reference to the calculator.dll file, you will also need to add a reference to the MWArray.Dll which is located at “C:\Program Files\MATLAB\MATLAB Compiler Runtime\v716\toolbox\dotnetbuilder\bin\win64\v2.0\MWArray.dll” (version dependent path) in order to facilitate the conversion of .NET types to MATLAB types.
  8. GUI for expression parser application.
  9. C# Application code.
    using System;
    using System.Windows.Forms;
    using MathWorks.MATLAB.NET.Arrays;
    using calculator;
    namespace DemoCalculator
        public partial class Form1 : Form
            public Form1()
            private void button1_Click(object sender, EventArgs e)
                var calc= new demo();            
  10. Run the application then enter a mathematical expression and hit the Calculate button, this will send the string to be interpreted by the MCR and return a result to the user, the end.