Fetching Contents from EXCEL File..!!

Often times in .Net application, we want to fetch data from EXCEL files. Reading contents from EXCEL files is quite simple and easy task. 

There are two ways, you can read contents from EXCEL file.

1. Using Microsoft Office Component
   
2. Using Microsoft Jet Engine
   

As per Microsoft recommendation, it is not advisable to use Office components on the server. It means that if you want to use this library for a server application, it's not a good idea to use the Office component. And it's better to do the connection using Jet Engine.

So in this post I will be discussing the second & recommended option, which is using Microsoft Jet Engine.

Connecting To EXCEL

To make a connection to the EXCEL, you can use OLEDB objects that will treat EXCEL file as database and then required contents or data can be fetched using SQL queries. Following is the connection string that you can use.

The connection string should be set to the
OleDbConnection
object. This is very critical as Jet Engine might not give a proper error message if the appropriate details are not given

Syntax for XLS files:
Provider=Microsoft.Jet.OLEDB.4.0; Data Source=<Full Path of Excel File>; Extended Properties="Excel 8.0; HDR=No; IMEX=1".

Data Source: Specify here the path of the excel file.

Extended Properties: Includes

1. HDR = [Yes/No]
   

This property will be used to specify the definition of header for each column. If the value is "Yes", the first row will be treated as heading. Otherwise, the heading will be generated by the system like F1, F2 and so on.

1. IMEX = [0/1/2]
   

This property indicates the Import Export mode and addresses how contents datatypes will be treated.

• IMEX=0 and IMEX=2: It will take the first 8 rows and then the data type for each column will be decided.
  
• IMEX=1 : In this case, everything will be treated as text.
  

For more info regarding Extended Properties,
click here.

Finally your connection to EXCEL file will be something like this.

cn = new
OleDbConnection();

cn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source='C:\MyEXcel.xls'; Extended Properties="Excel 8.0; HDR=No; IMEX=1";

Fetch EXCEL Sheets from EXCEL File

As we know so far that EXCEL file is like a database, the sheets in the excel file are equivalent to tables inside a database. So all we need to know is the sheet name and we can the write a query to fetch data from the sheet. So our next step is to fetch the Sheets contained in the EXCEL file. Following code will help you fetching all the sheets contained in the EXCEL file.

System.Data.DataTable dt = null;

cn.Open();

dt = cn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);

if(dt == null)

{

return
null;

}

String[] excelSheets = new
String[dt.Rows.Count];

int i = 0;

// Add the sheet name to the string array.

foreach(DataRow row in dt.Rows)

{

    string strSheetTableName = row["TABLE_NAME"].ToString();

    excelSheets[i] = strSheetTableName.Substring(0,strSheetTableName.Length-1);

    i++;

}

return excelSheets;

If you already know what sheets an EXCEL file is going to have then you can directly hardcode that in your code. Above code is required when you want to get list of all the sheets in EXCEL file.

Reading Contents from EXCEL Sheet

Now we know the database (Excel File connection) and table (sheetName) name from which we have to read contents. So we only have to write one query to fetch or read data from the excel sheet. Following is the code for this.

string strComand;

string strSheetName;

strSheetName = "sheet1";     //I know the sheet name so I mentioned it here directly.

strComand="select * from ["+strSheetName+"$]"; // You can specify specific column names as well in this query instead of *.

daAdapter=new
OleDbDataAdapter(strComand,cn);

    DataTable dt=new
DataTable(strSheetName);

    daAdapter.FillSchema(dt,SchemaType.Source);

    daAdapter.Fill(dt);

    cn.Close();

    return dt ;

Above code will give you DataTable
containing all the content of the specified sheet. Now you can load this data into DataSet as follows.

DataSet ds=new
DataSet();             

    ds.Tables.Add(dt);

I hope that you will find this post useful. Feel free to provide comments and your feedbacks.

Cheers,

Mirza Ateeq