SSRS Custom Data Processing Extension Error

Question

I am using Custom Data Processing Extension to call a stored procedure. Iam getting following error when creating a dataset in report designer using the extension. I wrote the code in c#.
could not update a list of fields for the query. verify that you can connect to the data source and that your query syntax is correct.(Details-Object reference not set to an instance of an object.)
Here is my code
using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Data;
using System.Data.SqlClient;
using Microsoft.ReportingServices.DataProcessing;
using System.Diagnostics;
using System.Text.RegularExpressions;
namespace DataBaseDPE
public class DBConnection:Microsoft.ReportingServices.DataProcessing.IDbConnectionExtension
private string mconnstring;
private string localname = "Database Connection";
private ConnectionState mState = ConnectionState.Open;
public DBConnection()
Debug.WriteLine("DataSetConnection: Default Constructor");
public DBConnection(string Dconnection)
Debug.WriteLine("DataSetConnection Constructor overloaded with Connection String ");
mconnstring = Dconnection;
public Microsoft.ReportingServices.DataProcessing.IDbTransaction BeginTransaction()
return (null);
public string ConnectionString
get
return mconnstring;
set
mconnstring = value;
public int ConnectionTimeout
get
return 0;
public ConnectionState State
get
return mState;
public void Open()
mState = ConnectionState.Open;
return;
public void Close()
mState = ConnectionState.Closed;
return;
public Microsoft.ReportingServices.DataProcessing.IDbCommand CreateCommand()
return new DBCommand(this);
public string LocalizedName
get
return localname;
set
localname = value;
public void SetConfiguration(string configuration)
try
SqlConnection sqlconn = new SqlConnection("Data Source=localhost;Initial Catalog=AdventureWorks2000;Integrated Security=True;");
catch (Exception e)
throw new Exception(e.Message, null);
public void Dispose()
public string Impersonate
{ get; set; }
public bool IntegratedSecurity
{ get; set; }
public string Password
{ get; set; }
public string UserName
{ get; set; }
using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.ReportingServices.DataProcessing;
using System.Data.SqlClient;
namespace DataBaseDPE
public class DBCommand : Microsoft.ReportingServices.DataProcessing.IDbCommand
DBConnection mconnection = null;
private string mCmdText;
private int mCmdTimeOut = 30;
private CommandType CmdType;
public DBCommand()
public DBCommand(string CmdText)
mCmdText = CmdText;
public DBCommand(DBConnection aConnection)
mconnection = aConnection;
public void Cancel()
throw new NotImplementedException();
public string CommandText
get
return mCmdText;
set
mCmdText = value;
public int CommandTimeout
get
return mCmdTimeOut;
set
mCmdTimeOut = value;
public CommandType CommandType
get
return CmdType;
set
CmdType = value;
public IDataParameter CreateParameter()
return (null);
public class MySqlDataReader:Microsoft.ReportingServices.DataProcessing.IDataReader
private System.Data.IDataReader sourceDataReader;
private System.Data.DataTable dt;
private System.Data.DataSet ds;
private int fieldCount = 0;
private string fieldName;
private int fieldOrdinal;
private Type fieldType;
private object fieldValue;
private int currentRow = 0;
public MySqlDataReader(System.Data.IDataReader datareader)
this.sourceDataReader = datareader;
public MySqlDataReader(System.Data.DataTable dt)
// TODO: Complete member initialization
this.dt = dt;
public MySqlDataReader(System.Data.DataSet ds)
// TODO: Complete member initialization
this.ds = ds;
public int FieldCount
get
fieldCount = ds.Tables[0].Columns.Count;
return fieldCount;
public Type GetFieldType(int i)
fieldType =
ds.Tables[0].Columns[i].DataType;
return fieldType;
public string GetName(int i)
fieldName = ds.Tables[0].Columns[i].ColumnName;
return fieldName;
public int GetOrdinal(string name)
fieldOrdinal =
ds.Tables[0].Columns[name].Ordinal;
return fieldOrdinal;
public object GetValue(int i)
fieldValue =
ds.Tables[0].Rows[this.currentRow][i];
return fieldValue;
public bool Read()
currentRow++;
if (currentRow >= ds.Tables[0].Rows.Count)
return (false);
else
return (true);
public void Dispose()
public IDataReader ExecuteReader(CommandBehavior behavior)
string query = "SampleSP";
SqlConnection readerconn = new SqlConnection("Data Source=localhost;Initial Catalog=AdventureWorks2000;Integrated Security=SSPI");
SqlCommand readercmd = new SqlCommand(query);
readerconn.Open();
readercmd = readerconn.CreateCommand();
readercmd.CommandText = query;
readercmd.CommandType = System.Data.CommandType.StoredProcedure;
readerconn.Close();
SqlDataAdapter adapter = new SqlDataAdapter(query,readerconn);
readerconn.Open();
adapter.SelectCommand = readercmd;
System.Data.DataTable dt = new System.Data.DataTable();
adapter.Fill(dt);
System.Data.DataSet ds = new System.Data.DataSet();
adapter.Fill(ds);
return new MySqlDataReader(ds);
public IDataParameterCollection Parameters
get { return (null); }
public IDbTransaction Transaction
get
return (null);
set
throw new NotImplementedException();
public void Dispose()
Please help me, Thanks in advance

Answer 1

Sorry why do you need a Data Processing Extension for that? Cant you directly call the procedure
from SSRS dataset? Whats the RDBMS which holds this procedure?
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