Answer to Question #41871 in C# for deepak

Question

The development team of SoftSols Inc. has revamped the software according to the requirements
of FlyHigh Airlines and is in the process of testing the software. While testing the software, the
team encounters the following issues:
The operations-related data of FlyHigh Airlines is stored in a central database. The software
fails to respond to user inputs, if there is a connectivity problem with the database. Add the code
snippet that the development team should use to ensure that the application shows a userfriendly
message, if such a situation arises in future.[5 Marks]
The application used to calculate the cost of carrying additional luggage results in erroneous
amount, if the weight of the luggage is a fractional number. Help the development team modify
the code snippet so that the cost of carrying additional luggage is calculated correctly. [5 Marks]

Answer 1

Answer on Question#41871- Programming, C# 

1. The development team of SoftSols Inc. hasrevamped the software according to the requirements
of FlyHigh Airlines and is in the process oftesting the software. While testing the software, the
team encounters the following issues:
The operations-related data of FlyHigh Airlinesis stored in a central database. The software
fails to respond to user inputs, if there is aconnectivity problem with the database. Add the code
snippet that the development team should use toensure that the application shows a userfriendly
message, if such a situation arises in future.[5Marks]
The application used to calculate the cost ofcarrying additional luggage results in erroneous
amount, if the weight of the luggage is afractional number. Help the development team modify
the code snippet so that the cost of carryingadditional luggage is calculated correctly. [5 Marks]
Solution.
 
using System;
usingSystem.Collections.Generic;
usingSystem.ComponentModel;
usingSystem.Data;
usingSystem.Data.SqlClient;
usingSystem.Drawing;
usingSystem.Linq;
usingSystem.Text;
usingSystem.Windows.Forms;
usingSystem.Runtime.InteropServices;
usingSystem.Data.Sql;
 
namespace DbProgram
{
 
    public partial class Form1 : Form
    {
        publicForm1()
        {
 
            InitializeComponent();
 
 
            this.textBox4.Text= "";
            if(Trusted_connection == true)
            {
                this.radioButton1.Checked= true;
                this.radioButton2.Checked= false;
                this.textBox4.Enabled= false;
                this.textBox5.Enabled= false;
            }
            else
            {
                this.radioButton1.Checked= false;
                this.radioButton2.Checked= true;
                this.textBox4.Enabled= true;
                this.textBox5.Enabled= true;
            }
        }
 
        boolTrusted_connection;
 
 
        privatevoid button2_Click_1(objectsender, EventArgs e)
        {
            Close();
        }
 
        privatevoid button3_Click(objectsender, EventArgs e)
        {
 
            if(radioButton1.Checked == true)
                Trusted_connection = true;
            else
                Trusted_connection = false;
            Close();
 
        }
 
        privatevoid radioButton1_CheckedChanged(object sender, EventArgse)
        {
            button3.Enabled = false;
            if(this.radioButton1.Checked == true)
            { Trusted_connection = true; }
            else
            { Trusted_connection = false; }
 
            if(Trusted_connection == true)
            {
                this.textBox4.Enabled= false;
                this.textBox5.Enabled= false;
            }
            else
            {
                this.textBox4.Enabled= true;
                this.textBox5.Enabled= true;
 
            }
        }
 
        privatevoid radioButton2_CheckedChanged(object sender, EventArgse)
        {
            button3.Enabled = false;
            if(this.radioButton2.Checked == false)
            { Trusted_connection = true; }
            else
            { Trusted_connection = false; }
 
            if(Trusted_connection == true)
            {
                this.textBox4.Enabled= false;
                this.textBox5.Enabled= false;
            }
            else
            {
                this.textBox4.Enabled= true;
                this.textBox5.Enabled= true;
 
            }
        }
 
        privatevoid button5_Click_1(objectsender, EventArgs e)
        {
            FolderBrowserDialogopenDirDialog = new FolderBrowserDialog();
            openDirDialog.SelectedPath =textBox3.Text;
 
            if(openDirDialog.ShowDialog() == DialogResult.OK)
            {
                try
                {
 
                    textBox3.Text =openDirDialog.SelectedPath.ToString();
 
 
                }
                catch(Exception ex)
                {
                    MessageBox.Show("Error opening the specified path! " +ex.Message);
                }
            }
        }
 
        privatevoid button6_Click(objectsender, EventArgs e)
        {
            button3.Enabled = false;
            comboBox2.Enabled = false;
            comboBox2.Items.Clear();
 
            button6.Text = "Search...";
            button6.Enabled = false;
 
            #region Gettingthe server name of the ODBC-sources
 
            String[]instances = SqlLocator.GetServers();
 
            foreach(String element ininstances)
            {
                comboBox2.Items.Add(element);
            }
 
            #endregion
            #region Getting alist of servers in a standard way
            DataTablet = SqlDataSourceEnumerator.Instance.GetDataSources();
            for(int i = 0; i < t.Rows.Count; i++)
            {
                stringServerName = t.Rows[i]["ServerName"].ToString();
                stringInstanceName = t.Rows[i]["InstanceName"].ToString();
                stringx = (InstanceName.Length > 0 ? (ServerName + "\\"+ InstanceName) : ServerName);
                comboBox2.Items.Add(x);
            }
            #endregion
 
            if(comboBox2.Items.Count != 0)
            {
                comboBox2.Text =comboBox2.Items[0].ToString();
 
                try
                {
                    GetDataBase();
                }
                catch
                {
                    MessageBox.Show("The selected server is not available. \nPleasechoose another server", "Attention",MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
            }
 
            button6.Text = "Get the list";
            comboBox2.Enabled = true;
            button6.Enabled = true;
 
        }
        #region Getting a list ofdatabases
        privatevoid GetDataBase()
        {
            comboBox1.Items.Clear();
            comboBox1.Text = "";
            stringSecurity;
            if(radioButton1.Checked == true)
            {
                Security = "Integrated Security=true";
            }
            else
            {
                Security = @"Persist Security Info=True;User ID=" +textBox5.Text + ";Password=" +textBox4.Text + "";
 
            }
 
            if(comboBox1.Text != "")
            { Security = "Initial Catalog=" + comboBox1.Text + ";" + Security; }
 
            SqlConnectionsqlConn = new SqlConnection(@"Server=" + comboBox2.Text + ";" + Security);
 
            try
            {
                sqlConn.Open();
 
                SqlCommandsqlCmd = new SqlCommand();
                sqlCmd.Connection = sqlConn;
                sqlCmd.CommandType = CommandType.StoredProcedure;
                sqlCmd.CommandText = "sp_helpdb";
 
                SqlDataAdapterda = new SqlDataAdapter(sqlCmd);
                DataSetds = new DataSet();
                da.Fill(ds);
 
                foreach(DataRow row inds.Tables[0].Rows)
                {
                    comboBox1.Items.Add(row["name"].ToString());
                }
                sqlConn.Close();
 
 
 
                if(comboBox2.Text == "")
                {
                    comboBox1.Enabled = false;
                    button3.Enabled = false;
                    button7.Enabled = false;
                }
                else
                {
                    comboBox1.Enabled = true;
                    button7.Enabled = true;
                }
            }
            catch
            {
                MessageBox.Show("The selected server is not available.\nSelect adifferent server.", "Attention",MessageBoxButtons.OK, MessageBoxIcon.Information);
                stringtest = comboBox2.Text;
            }
        }
        #endregion
 
 
 
        privatevoid button7_Click(objectsender, EventArgs e)
        {
            StringSecurity = "";
            if(comboBox1.Text == "")
            {
                comboBox1.Text = "master";
            }
 
            if(radioButton2.Checked == true)
            {
                Security = @"Persist Security Info=True;User ID=" +textBox5.Text + ";Password=" +textBox4.Text + "";
            }
            elseif (radioButton1.Checked == true)
            {
                Security = "Integrated Security=true";
            }
 
            SqlConnectionsqlConn = new SqlConnection(@"Server=" + comboBox2.Text + ";Initial Catalog=" + comboBox1.Text + ";" + Security);
 
            try
            {
                string_databasename = comboBox1.Text;
                sqlConn.Open();
                MessageBox.Show("Testing the connection is made.", "Connecting to a database", MessageBoxButtons.OK, MessageBoxIcon.Information);
                SqlCommandsqlCmd = new SqlCommand();
                sqlCmd.Connection = sqlConn;
                sqlCmd.CommandType = CommandType.StoredProcedure;
                sqlCmd.CommandText = "sp_helpdb";
 
                SqlDataAdapterda = new SqlDataAdapter(sqlCmd);
                DataSetds = new DataSet();
                da.Fill(ds);
 
                foreach(DataRow row inds.Tables[0].Rows)
                {
                    comboBox1.Items.Add(row["name"].ToString());
                }
                sqlConn.Close();
                comboBox1.Text = _databasename;
                button3.Enabled = true;
            }
            catch
            {
                MessageBox.Show("Testing the connection failed.\n\nSQL Server is notavailable.\nMaybe not correctly specify a username and password.", "Connecting to a database", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
 
 
        }
 
        privatevoid ServerOptionsForm_Load(object sender, EventArgse)
        {
 
        }
 
 
 
    }
 
    public class SqlLocator
    {
        [DllImport("odbc32.dll")]
        privatestatic extern short SQLAllocHandle(shorthType, IntPtr inputHandle, out IntPtroutputHandle);
        [DllImport("odbc32.dll")]
        privatestatic extern short SQLSetEnvAttr(IntPtrhenv, int attribute, IntPtrvaluePtr, int strLength);
        [DllImport("odbc32.dll")]
        privatestatic extern short SQLFreeHandle(shorthType, IntPtr handle);
        [DllImport("odbc32.dll", CharSet = CharSet.Ansi)]
        privatestatic extern short SQLBrowseConnect(IntPtrhconn, StringBuilder inString,
            shortinStringLength, StringBuilder outString, short outStringLength,
            outshort outLengthNeeded);
 
        privateconst shortSQL_HANDLE_ENV = 1;
        privateconst shortSQL_HANDLE_DBC = 2;
        privateconst intSQL_ATTR_ODBC_VERSION = 200;
        privateconst intSQL_OV_ODBC3 = 3;
        privateconst shortSQL_SUCCESS = 0;
 
        privateconst shortSQL_NEED_DATA = 99;
        privateconst shortDEFAULT_RESULT_SIZE = 1024;
        privateconst stringSQL_DRIVER_STR = "DRIVER=SQL SERVER";
 
        privateSqlLocator() { }
 
        public static string[]GetServers()
        {
            string[]retval = null;
            stringtxt = string.Empty;
            IntPtrhenv = IntPtr.Zero;
            IntPtrhconn = IntPtr.Zero;
            StringBuilderinString = new StringBuilder(SQL_DRIVER_STR);
            StringBuilderoutString = new StringBuilder(DEFAULT_RESULT_SIZE);
            shortinStringLength = (short)inString.Length;
            shortlenNeeded = 0;
 
            try
            {
                if(SQL_SUCCESS == SQLAllocHandle(SQL_HANDLE_ENV, henv, outhenv))
                {
                    if(SQL_SUCCESS == SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (IntPtr)SQL_OV_ODBC3, 0))
                    {
                        if (SQL_SUCCESS == SQLAllocHandle(SQL_HANDLE_DBC, henv, out hconn))
                        {
                            if (SQL_NEED_DATA == SQLBrowseConnect(hconn,inString, inStringLength, outString,
                               DEFAULT_RESULT_SIZE, out lenNeeded))
                            {
                                if (DEFAULT_RESULT_SIZE < lenNeeded)
                                {
                                   outString.Capacity = lenNeeded;
                                    if (SQL_NEED_DATA != SQLBrowseConnect(hconn,inString, inStringLength, outString,
                                       lenNeeded, out lenNeeded))
                                    {
                                        throw new ApplicationException("Unabledto aquire SQL Servers from ODBC driver.");
                                    }
                                }
                                txt =outString.ToString();
                                int start = txt.IndexOf("{")+ 1;
                                int len = txt.IndexOf("}")- start;
                                if ((start > 0) && (len > 0))
                                {
                                    txt =txt.Substring(start, len);
                                }
                                else
                                {
                                    txt = string.Empty;
                                }
                            }
                        }
                    }
                }
            }
            catch(Exception ex)
            {
                //Throwaway any error if we are not in debug mode
#if (DEBUG)
                MessageBox.Show(ex.Message,"Acquire SQL Servier List Error");
#endif
                txt = string.Empty;
            }
            finally
            {
                if(hconn != IntPtr.Zero)
                {
                   SQLFreeHandle(SQL_HANDLE_DBC, hconn);
                }
                if(henv != IntPtr.Zero)
                {
                   SQLFreeHandle(SQL_HANDLE_ENV, hconn);
                }
            }
 
            if(txt.Length > 0)
            {
                retval = txt.Split(",".ToCharArray());
            }
 
            returnretval;
        }
   }
 
 
 
   
}