Export DataTable to Excel with Formatting in C#

Santhosh Kumar Jayaraman

4.83/5 (34 votes)

21 Nov 2014CPOL1 min read

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Export a DataTable to an Excel file and add format to the contents while writing the Excel file.

Download source code - 159 KB

Introduction

In this tip, let us see how to export a DataTable to an Excel file and add format to the contents while writing the Excel file.

Step 1: Create a web application and add a class Student with properties as below:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Reflection;

namespace ExportToExcelFromDataTable
{
    public partial class _Default : System.Web.UI.Page
    {
       protected void Page_Load(object sender, EventArgs e)
       {
       }
    }
    public class Student
    {
        public string Name { get; set; }
        public int StudentId { get; set; }
        public int Age { get; set; }
    }
}

Step 2: I have added Gridview_Result. Create a list for students in the page_load event. Add a property dt of type DataTable. Bind the DataTable to the GridView after converting the List to a DataTable. The conversion class is described in the next step.

protected void Page_Load(object sender, EventArgs e)
{
    List<Student> Students = new List<Student>(){
        new Student() { Name = "Jack", Age = 15, StudentId = 100 },
        new Student() { Name = "Smith", Age = 15, StudentId = 101 },           
        new Student() { Name = "Smit", Age = 15, StudentId = 102 }
    };
    ListtoDataTableConverter converter = new ListtoDataTableConverter();
    dt = converter.ToDataTable(Students);
    GridView_Result.DataSource = Students;
    GridView_Result.DataBind();
}

Step 3: Now we are going to convert this List object to a DataTable. For that we need to create a new class and a conversion method as below.

public class ListtoDataTableConverter
{
    public DataTable ToDataTable<T>(List<T> items)
    {
        DataTable dataTable = new DataTable(typeof(T).Name);
        //Get all the properties
        PropertyInfo[] Props = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);
        foreach (PropertyInfo prop in Props)
        {
            //Setting column names as Property names
            dataTable.Columns.Add(prop.Name);
        }

         foreach (T item in items)
        {
            var values = new object[Props.Length];
            for (int i = 0; i < Props.Length; i++)
            {
                //inserting property values to datatable rows
                values[i] = Props[i].GetValue(item, null);
            }

            dataTable.Rows.Add(values);

        }
         //put a breakpoint here and check datatable
        return dataTable;
    }
}

The above method will set the property name as a column name for the DataTable and for each object in the list; it will create a new row in the DataTable and insert values.

Step 4: I have written the below method which will convert a DataTable to an Excel file. In this method, I added font, made headers bold, and added a border. You can customize the method as per your needs.

private void ExporttoExcel(DataTable table)
{
    HttpContext.Current.Response.Clear();
    HttpContext.Current.Response.ClearContent();
    HttpContext.Current.Response.ClearHeaders();
    HttpContext.Current.Response.Buffer = true;
    HttpContext.Current.Response.ContentType = "application/ms-excel";
    HttpContext.Current.Response.Write(@"<!DOCTYPE HTML PUBLIC ""-//W3C//DTD HTML 4.0 Transitional//EN"">");
    HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment;filename=Reports.xls");
   
    HttpContext.Current.Response.Charset = "utf-8";
    HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("windows-1250");
      //sets font
    HttpContext.Current.Response.Write("<font style='font-size:10.0pt; font-family:Calibri;'>");
    HttpContext.Current.Response.Write("<BR><BR><BR>");
    //sets the table border, cell spacing, border color, font of the text, background, foreground, font height
    HttpContext.Current.Response.Write("<Table border='1' bgColor='#ffffff' " + 
      "borderColor='#000000' cellSpacing='0' cellPadding='0' " + 
      "style='font-size:10.0pt; font-family:Calibri; background:white;'> <TR>");
    //am getting my grid's column headers
    int columnscount = GridView_Result.Columns.Count;

    for (int j = 0; j < columnscount; j++)
    {      //write in new column
        HttpContext.Current.Response.Write("<Td>");
        //Get column headers  and make it as bold in excel columns
        HttpContext.Current.Response.Write("<B>");
        HttpContext.Current.Response.Write(GridView_Result.Columns[j].HeaderText.ToString());
        HttpContext.Current.Response.Write("</B>");
        HttpContext.Current.Response.Write("</Td>");
    }
    HttpContext.Current.Response.Write("</TR>");
    foreach (DataRow row in table.Rows)
    {//write in new row
        HttpContext.Current.Response.Write("<TR>");
        for (int i = 0; i < table.Columns.Count; i++)
        {
            HttpContext.Current.Response.Write("<Td>");
            HttpContext.Current.Response.Write(row[i].ToString());
            HttpContext.Current.Response.Write("</Td>");
        }

        HttpContext.Current.Response.Write("</TR>");
    }
    HttpContext.Current.Response.Write("</Table>");
    HttpContext.Current.Response.Write("</font>");
    HttpContext.Current.Response.Flush();
    HttpContext.Current.Response.End();
}

Step 4: Add a button and in the button click event, call the above method by passing a parameter.

protected void Btn_Export_Click(object sender, EventArgs e)
{
    ExporttoExcel(dt);
}

For the complete source code, please find the attached solution.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)