Create XML file using LINQ

public void AddProductCategory(string filePath, string productCategory)
{
XDocument oXDoc;
try
{
if (File.Exists(filePath))
{
oXDoc = XDocument.Load(filePath);
oXDoc.Element("DataContent").Add(
new XElement("Data",
new XElement("ID", Guid.NewGuid().ToString()),
new XElement("CategoryName", productCategory)
));
oXDoc.Save(filePath);
}
else
{
XElement oXElmnt = new XElement("DataContent",
new XElement("Data",
new XElement("ID", Guid.NewGuid().ToString()),
new XElement("CategoryName", productCategory)
));
oXElmnt.Save(filePath);
}
}
catch (Exception ex) { }
}

Create Excel file with save Dialog in ASP.Net

DataTable will have the data to write into Excel file
fileName will be Excel file name with extension(.xls/.xlsx)

public void SaveExcelFile(string fileName, DataTable dtData)
{
try
{
HttpContext.Current.Response.Clear();
HttpContext.Current.Response.ContentType = "application/ms-excel";
HttpContext.Current.Response.AddHeader("Content-Disposition", "inline; filename=" + fileName + "");
HttpContext.Current.Response.Flush();
for (int colCount = 0; colCount < dtData.Columns.Count; colCount++)
{
HttpContext.Current.Response.Write(dtData.Columns[colCount].ColumnName.ToString());
HttpContext.Current.Response.Write("\t");
}
for (int rowCount = 0; rowCount < dtData.Rows.Count; rowCount++)
{
HttpContext.Current.Response.Write("\n");
for (int colCount = 0; colCount < dtData.Columns.Count; colCount++)
{
HttpContext.Current.Response.Write(dtData.Rows[rowCount][colCount].ToString());
HttpContext.Current.Response.Write("\t");
}

}
HttpContext.Current.Response.End();
}
catch (Exception ex)
{ }
}

Some C# Coding Standards Should follow

Coding standards

• Ø                          Naming Convention

1.       Use Pascal casing for Class name, Methods, Properties etc

                  Public void DisplayName()

                   {

                    }

2.       Use Camel casing for variables

string customerName

Int customerId

3.       Don’t use Hungerian notation

 string m_sName;

Int nCount;

• Ø                      Always use meaningful names for variables, properties, Methods etc.

Like:- string customerName

Avoid :- string cust_Name

• Ø                   Do not use underscore ( _ ) for local variables
• 
  
•                          Prefix Boolean variables, properties and methods with “is” or similar prefixes.

Private bool isFinished;

• Ø          Namespace names should follow the standard pattern

...

• Ø                   File name should match with class name.

For example, for the class HelloWorld, the file name should be helloworld.cs (or, helloworld.vb)

• Ø               Always use Pascal casing in filename.

• Ø             Don’t use variables like i,j in loop. Always use meaningful names

Wrong approach:

For(int i=0; i<10; i++)

{

}

Right approach:

For(int count=0; count<10; count++)

{
}

• Ø                 Always put Comments for classes, functions, properties etc.

///Summary

/// description of class,methods

///created by : user

///created on : date

///last modified by : user

///last created on : date

Creating Excel Workbook using C#.net

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Data.OleDb;
using System.IO;
using System.Reflection;
using System.Text;
using System.Threading;
using System.Windows.Forms;
using Exl = Microsoft.Office.Interop.Excel;

public class createExcel
{

//Excel Objects
        Exl.Application excel;
        Exl.Workbook workBook;
        Exl.Workbooks workBooks;
        Exl.Sheets sheets;
        Exl._Worksheet workSheet;
        Exl.Range range;
        Exl.Range rangeCells;



public createExcel()
{
InitializeExcelObjects();
}

public void InitializeExcelObjects()
        {
            excel = new Exl.Application();
            workBooks = excel.Workbooks;
            workBook = excel.Workbooks.Add(Type.Missing);

            //sheets = excel.Sheets;
            //wSheet = (Exl._Worksheet)(sheets[1]);
        }


private int ExcelTemplate(string fileName, DataTable dtData)
        {
            int nmReturn=0, nmSheetIndex=1, nmColumnCount=1;
            StringBuilder strBuild = new StringBuilder();
            string sheetName = string.Empty;
            try
            {
        
                sheetName = dtData.Rows[0][1].ToString();
                sheets = excel.Sheets;
                workSheet = ((Exl.Worksheet)sheets[nmSheetIndex]);
                workSheet.Name = sheetName;
                range = workSheet.Cells;
                rangeCells = workSheet.Cells;
                for (int rowCount = 0; rowCount < dtData.Rows.Count; rowCount++)
                {
                    if (!sheetName.Equals(dtData.Rows[rowCount][1].ToString()))
                    {
                        nmSheetIndex++;
                        sheetName = dtData.Rows[rowCount][1].ToString();
                        workSheet = ((Exl.Worksheet)sheets[nmSheetIndex]);
                        workSheet.Name = sheetName;
                        range = workSheet.Cells;
                        rangeCells = workSheet.Cells;
                        nmColumnCount = 1;
                    }
                        //workSheet.Columns.ColumnWidth = 50;
                        rangeCells.HorizontalAlignment = Microsoft.Office.Interop.Excel.Constants.xlLeft;
                        rangeCells[1, nmColumnCount] = dtData.Rows[rowCount][0].ToString();
                        nmColumnCount++;
                                   }
                string filePath = Application.StartupPath.ToString() + fileName;
                workBook.SaveAs(filePath, Exl.XlFileFormat.xlWorkbookNormal, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Exl.XlSaveAsAccessMode.xlNoChange, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
                excel.Workbooks.Close();
                nmReturn++;
            }
            catch (Exception ex) { nmReturn = 0; }
            return nmReturn;
        }
}

Dynamic DataTable in Asp.Net

DataTable myDt;

protected void Page_Load(object sender, EventArgs e)

{

if (!Page.IsPostBack)

{

myDt = new DataTable();

myDt = createDataTable();

Session["myDatatable"] = myDt;

this.GridView1.DataSource = ((DataTable)Session["myDatatable"]).DefaultView;

this.GridView1.DataBind();

}

}

protected void Button1_Click(object sender, EventArgs e)

{

addDataTableData();

populateGridView();

}

private DataTable createDataTable()

{

DataTable dt = new DataTable();

dt.Columns.Add("Id", Type.GetType("System.String"));

dt.Columns.Add("Name", Type.GetType("System.String"));

return dt;

}

private void populateGridView()

{

GridView1.DataSource = ((DataTable)Session["myDatatable"]).DefaultView;

GridView1.DataBind();

}

private void addDataTableData()

{

DataTable myTable = ((DataTable)Session["myDatatable"]);

DataRow row;

row = myTable.NewRow();

row["id"] = TextBox1.Text;

row["Name"] = TextBox2.Text;

myTable.Rows.Add(row);

}