Delegates in C#.NET

Delegates in C# -

Delegates are used to Call non-member function of the Class/ Form. (functions of other class/ Form)
like e.g.

If we want to call load event of Form1 =>Form1_Load() event On closing of Form2 => Form2_Closing().


Coding =>

1. In Form1 Coding

public delegate voidForm1FormLoadHandler();

        public eventForm1FormLoadHandlerForm1FormLoad;

        public void OnFrm_BudgetDetailsFormLoad()
        {
            object s = null;
            EventArgs e = null;
           Form1_Load(s, e);
        }



In Form2 Coding


        private void Form2_FormClosing(object sender, FormClosingEventArgs e)
        {
                Form1 frm = (Form1)this.frm;
                Form1.Form1LoadHandler f = null;
                f += new Form1.Form1LoadHandler(frm.OnForm1Load);
                frm.OnForm1Load();
        }

C#.NEt - To Open any system application in C#.NET

// To open existing file of any type.
System.Diagnostics.Process.Start(string FileName);

// To open application, (and/or create new file).
System.Diagnostics.Process.Start("notepad",string FileName);

C#.NET - Export To Excel Contents of DataGridView Control

// Must include following libraries.

using System.IO;
using Microsoft.Office.Interop.Excel;

// Creating Object of System Application (e.g. Microsoft Excel)

private ApplicationClass xlApp = new ApplicationClass();

        private void createDataInExcel(DataSet ds)
        {
            Workbook xlWorkBook;
            Worksheet xlWorkSheet;
           
            object misValue = System.Reflection.Missing.Value;

            xlWorkBook = xlApp.Workbooks.Add(misValue);
            xlWorkSheet = (Microsoft.Office.Interop.Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);
            int i = 0;
            int j = 0;

       // set rows and columns of excel sheet = the rows and columns of datagridview control

            for (j = 1; j <= DataGirdViewControl.Columns.Count - 3; j++)
            {
                xlWorkSheet.Cells[i + 1, j + 1] = DataGirdViewControl.Columns[j].HeaderText.ToString();
            }

            for (i = 0; i <= DataGirdViewControl.RowCount  - 1; i++)
            {
                for (j = 1; j <= DataGirdViewControl.Columns.Count  - 3; j++)
                {
                    DataGridViewCell cell = DataGirdViewControl[j, i];
                    xlWorkSheet.Cells[i + 3, j + 1] = cell.Value;
                }
            }

        // Creating destination path, you can assign manually

            string strPath = System.Windows.Forms.Application.StartupPath;
            strPath = strPath.Replace(@"\bin\Debug", "");
            strPath = strPath + "\\Folder";

        // checking for exsting path, if exists it will replace it.
            if (!Directory.Exists(strPath))
                Directory.CreateDirectory(strPath);

            string strFileName = strPath + "\\Folder(" +  FileName  + ").xls";
           
            try
            {
        // To save Excel sheet.

                xlWorkBook.SaveAs(strFileName, Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookNormal, misValue, misValue, misValue, misValue, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlExclusive, misValue, misValue, misValue, misValue, misValue);
                xlWorkBook.Close(true, misValue, misValue);
                xlApp.Quit();
            }
            catch (Exception oException)
            {
                MessageBox.Show("You can not access " + strFileName + ". This file might be already open.", "Budget Details", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }

            releaseObject(xlWorkSheet);
            releaseObject(xlWorkBook);
            releaseObject(xlApp);

            MessageBox.Show("Excel file created , you can find the file \\Folder" + strFileName,"",MessageBoxButtons.OK,MessageBoxIcon.Information);
            xlWorkBook = null;
            xlWorkSheet = null;           
        }

private void releaseObject(object obj)
        {
            try
            {
                System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
                obj = null;
            }
            catch (Exception ex)
            {
                obj = null;
                MessageBox.Show("Exception Occured while releasing object " + ex.ToString());
            }
            finally
            {
                GC.Collect();
            }
        }

C#.NET - Rebind DataGridView Control after User Deleted Row

// Datagridview control is binded with DataSource.
// Deleting a row from DatagridView control and hence from DataBase,

private void DataGridView_KeyDown(View sender, KeyEventArgs e)
        {
            if (e.KeyValue == 46)
            {
                if (DataGridView.SelectedRows.Count > 0)
                {
                    if (MessageBox.Show("Are you sure you want to Delete  Record?", "Complaint Details", MessageBoxButtons.YesNo, MessageBoxIcon.Warning).ToString().ToLower() == "yes")
                    {
                        nIndex = DataGridView.SelectedRows[0].Index;
                        DeleteRow(nIndex);
                    }          
                }
            }
        }

// DeleteROw is user defined function, delete the record from database.

    private void DeleteRow(int nIndex)
        {
            int nDeleted;
            BusinessLayer oBusinessLayer = new BusinessLayer();

            nDeleted = oBusinessLayer.DeleteRecord("(" + DataGridView.Rows[nIndex].Cells["colID"].Value.ToString() + ")");
            if (nDeleted != 0)
            {
                MessageBox.Show("Record(s) can not be Deleted.", "Database", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
            else
            {
                MessageBox.Show("Record(s) Successfully Deleted.", "Databse", MessageBoxButtons.OK, MessageBoxIcon.Information);

        // Rebind the datasource with updated Databse
          
        Dtg_ComplaintDetails.DataSource = oDataTable;
                LoadDataGrid(oDataTable);            
            }
        }

Crystal Reports in C#.NET

Java - To Check ArmString Number

class ArmString
{
    public static void main(String arg[])
    {
        int n;
        n = Integer.parseInt(arg[0]);
        int digit, sum, num;
        sum = 0;
        System.out.println();
        num = n;
        System.out.println("Number : " + n);
        while (n > 0)
        {
            digit = n % 10;
            sum = sum + (digit * digit * digit);
            n = n / 10;
        }
        System.out.println();
        System.out.println("Sum    : " + sum);
        if (sum == num)
        {
            System.out.println("Given number is an ArmStrong");
        }
        else
        {
            System.out.println();
            System.out.println("Given number is not an ArmStrong");

        }
    }
}

Crystal Reports in C#.NET - Display Join of Two Tables

One to Many relationship of  Tables ...


1. Add both the tables to DataSet being used.

 
2.Both tables must have Link between them, (e.g Primary Key of 1 Tables as Foreign Key of other)

How to Group the fields ??
-> 1.Right click in Details Section.
2. from the menu Select Report -> "Group Expert".
3. It will open the window "Group Expert" dialog box
4. In that select  those fields, that you want to group together. (as done in above fig.)
5.click on OK.
6. arrange the fields as you want.