Simple Class used by a form

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace SampleProj
{
public partial class Form3 : Form
{
public Form3()
{
InitializeComponent();
}

private void Form3_Load(object sender, EventArgs e)
{
Sample obj = new Sample();
dataGridView1.DataSource = obj.getEmployeeDetail();
}

private void btnFind_Click(object sender, EventArgs e)
{
Sample obj = new Sample();
txtEmpName.Text = obj.getEmployeeDetail(1);
//use emp id instead of the constant 1
}


}
}


////////////////////////////////////////////////////////////////////



using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.SqlClient;
namespace SampleProj
{
class Sample
{
public String getEmployeeName(int nEmpID)
{
string strName = "";
//code to get the Employee Name
return strName;
}

public DataTable getEmployeeDetail()
{
DataTable ds = new DataTable();
//code to Fill DataTable
return ds;
}
}
}

the following is a sample class file for database operation

using System;

using System.Collections.Generic;

using System.Data;

using System.Collections;

using System.Configuration;

using System.Windows.Forms;

using System.Data.SqlClient;

 

///

/// Summary description for dbProvider

///

///

 

 

 public class dbClass

{

 

    //string constring = ConfigurationSettings.AppSettings["constring"];

 

    //string constring = ConfigurationSettings.AppSettings["constring"].ToString();

    SqlConnection conn = new SqlConnection(ConfigurationSettings.AppSettings["constring"]);

    //SqlConnection conn = new SqlConnection("uid=sa;database=Tendercenter;Password=vss;Data Source=versatile3");

    const int _timeout = 180;

 

    public dbClass()

    {

        try

        {

            //string str = ConfigurationSettings.AppSettings["constring"];

            //System.Windows.Forms.MessageBox.Show(str);

            //string constring = ConfigurationManager.ConnectionStrings["con"];

            //SqlConnection conn = new SqlConnection(constring);

            if (conn.State == ConnectionState.Open)

            {

                conn.Close();

            }

            conn.Open();

        }

        catch (Exception ex)

        {

        }

    }

 

    public dbClass(String strType)

    {

        if (strType == "TCOnlineSqlServer")

        {

            conn.ConnectionString = ConfigurationSettings.AppSettings["OnlineSql"];

            MessageBox.Show(conn.ConnectionString);

            //ConfigurationManager.AppSettings["TenderCenterConnectionString"];

            if (conn.State == ConnectionState.Open)

            {

                conn.Close();

            }

            try

            {

                conn.Open();

            }

            catch (Exception ex)

            {

                MessageBox.Show("Please check the " + strType + " Connection String " + ex.Message, "DB Connection", MessageBoxButtons.OK, MessageBoxIcon.Error);

            }

        }

    }

 

    public void dispose()

    {

        if (conn.State == ConnectionState.Open)

        {

            conn.Close();

            conn = null;

        }

    }

    public void dispose(String strType)

    {

        if (strType == "TCOnlineSqlServer")

        {

            conn.Close();

            conn = null;

        }

    }

    public SqlDataReader getData(SqlCommand cmd)

    {

        SqlDataReader myReader;

        cmd.Connection = conn;

        cmd.CommandTimeout = _timeout;

        myReader = cmd.ExecuteReader();

        return myReader;

    }

 

    public SqlDataReader getData(string sql)

    {

        SqlCommand cmd;

        SqlDataReader myReader;

        cmd = new SqlCommand(sql);

        cmd.CommandType = CommandType.Text;

        cmd.Connection = conn;

        cmd.CommandTimeout = _timeout;

        myReader = cmd.ExecuteReader();

        return myReader;

    }

 

    //Input Sql Statement and get data object DataTable

    public DataTable getData(object strQuery)

    {

        DataTable dt = new DataTable();

        if (conn.State == ConnectionState.Open)

        {

            SqlDataAdapter da = new SqlDataAdapter(strQuery.ToString(), conn);

            da.Fill(dt);           

        }

        return dt;

       

    }

 

 

    //Input Sql Statement and get data object DataSet

    public DataSet getData(string sql, string tableName)

    {

 

        DataSet myDataset = new DataSet();

        if (conn.State == ConnectionState.Open)

        {

            SqlDataAdapter myAdapter;

            myAdapter = new SqlDataAdapter(sql, conn);

            myAdapter.Fill(myDataset, tableName);

           

        }

        return myDataset;

      

    }

 

    //Input Sql Statement and get data object DataSet

    public DataSet getData(SqlCommand cmd, string tableName)

    {

        SqlDataAdapter myAdapter;

        DataSet myDataset = new DataSet();

        cmd.Connection = conn;

        cmd.CommandTimeout = _timeout;

        myAdapter = new SqlDataAdapter(cmd);

        myAdapter.Fill(myDataset, tableName);

        return myDataset;

    }

 

    //Input Stored procedure and Mode to get data object Datatable

    public DataTable getData(string StoredProcedure, String[,] Parameters, string tableName)

    {

        DataTable dt = new DataTable();

 

        SqlCommand cmd = new SqlCommand(StoredProcedure);

        cmd.Connection = conn;

        cmd.CommandTimeout = _timeout;

        cmd.CommandType = CommandType.StoredProcedure;

        for (int i = 0; i <>

        {

            cmd.Parameters.AddWithValue(Parameters[i, 0].ToString(), Parameters[i, 1].ToString());

        }

 

        //cmd.Parameters.AddWithValue("@Mode", Mode);

        SqlDataAdapter da = new SqlDataAdapter(cmd);

        da.Fill(dt);

        dt.TableName = tableName;

        return dt;

    }

 

    public DataTable getDataTable(string StoredProcedure, Object[,] Parameters)

    {

        DataTable dt = new DataTable();

 

        SqlCommand cmd = new SqlCommand(StoredProcedure);

        cmd.Connection = conn;

        cmd.CommandTimeout = _timeout;

        cmd.CommandType = CommandType.StoredProcedure;

        for (int i = 0; i <>

        {

            cmd.Parameters.AddWithValue(Parameters[i, 0].ToString(), Parameters[i, 1]);

 

        }

 

        //cmd.Parameters.AddWithValue("@Mode", Mode);

        SqlDataAdapter da = new SqlDataAdapter(cmd);

        da.Fill(dt);

        //dt.TableName = tableName;

        return dt;

    }

 

    public SqlDataReader getData(string StoredProcedure, Object[,] Parameters)

    {

 

        SqlDataReader dr;

        SqlCommand cmd = new SqlCommand(StoredProcedure);

        cmd.Connection = conn;

        cmd.CommandTimeout = _timeout;

        cmd.CommandType = CommandType.StoredProcedure;

        for (int i = 0; i <>

        {

            cmd.Parameters.AddWithValue(Parameters[i, 0].ToString(), Parameters[i, 1].ToString());

 

        }

        dr = cmd.ExecuteReader();

        return dr;

    }

 

    public int setData(string StoredProcedure, Object[,] Parameters)

    {

        SqlCommand cmd = new SqlCommand(StoredProcedure);

        cmd.Connection = conn;

        cmd.CommandTimeout = _timeout;

        cmd.CommandType = CommandType.StoredProcedure;

        for (int i = 0; i <>

        {

 

            cmd.Parameters.AddWithValue(Parameters[i, 0].ToString(), Parameters[i, 1]);

        }

        return (int)cmd.ExecuteNonQuery();

    }

 

    public string setData(string StoredProcedure, Object[,] Parameters, string outParam)

    {

        SqlCommand cmd = new SqlCommand(StoredProcedure);

        cmd.Connection = conn;

        cmd.CommandTimeout = _timeout;

        cmd.CommandType = CommandType.StoredProcedure;

        for (int i = 0; i <>

        {

 

            cmd.Parameters.AddWithValue(Parameters[i, 0].ToString(), Parameters[i, 1]);

        }

        SqlParameter parmId;

        parmId = cmd.Parameters.Add(outParam, SqlDbType.VarChar, 50);

        parmId.Direction = ParameterDirection.Output;

        cmd.ExecuteNonQuery();

        return Convert.ToString(cmd.Parameters[outParam].Value);

    }

 

    //this function used to store the data into the database

    public void setData(SqlCommand cmd)

    {

        cmd.Connection = conn;

        cmd.CommandTimeout = _timeout;

        cmd.ExecuteNonQuery();

    }

 

    public string setData(SqlCommand cmd, string outParam)

    {

        SqlParameter parmId;

        parmId = cmd.Parameters.Add(outParam, SqlDbType.VarChar, 50);

        parmId.Direction = ParameterDirection.Output;

        cmd.Connection = conn;

        cmd.CommandTimeout = _timeout;

        cmd.ExecuteNonQuery();

        return Convert.ToString(cmd.Parameters[outParam].Value);

    }

 

   

 

     

 

     public string getID(string strTableName, string strColumnName, string strWhereColName, string strWhereColValue)

     {

         try

         {

             dbClass objDB = new dbClass();

             if (strWhereColValue != String.Empty)

             {

 

                 SqlDataReader objDr;

                 objDr = objDB.getData("select " + strColumnName + " from " + strTableName + " where " + strWhereColName + " = '" + strWhereColValue + "'");

                 if (objDr.HasRows)

                 {

                     objDr.Read();

                     return objDr[0].ToString();

                 }

                 else

                     return "0";

             }

             else

             {

                 return "0";

             }

             objDB.dispose();

         }

         catch (Exception ex)

         {           

             return "0";

         }

     }

 

    

     public SqlConnection GetSqlConnection()

     {

         return conn;

     }

}