Reading an Excel File From C#

Question

I have a connection string to read an excel file from my C# project that looks like this..

String ConnectionString  = \"Provider=Microsoft.ACE.OLEDB.12.0;\"          


        

Answer 1

I recently had to use this provider for an Azure Web Job where I needed to use an OLEDB Provider rather than the Excel.

You can install the Microsoft.ACE.OLEDB.12.0 Provider using the following setup.

Microsoft Access Database Engine 2010 Redistributable https://www.microsoft.com/en-us/download/details.aspx?id=13255

Once installed, you can modify the connection string for .xls and .xlsx file extensions.

For example, the following code will convert an Excel file to a DataSet with a DataTable for each Worksheet in the excel file.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Configuration;
using System.Data;
using System.Data.OleDb;
using System.Linq;
using System.Net;

...

public DataSet ExcelToDataSet(string excelFilename)
{
    var dataSet = new DataSet(excelFilename);

    // Setup Connection string based on which excel file format we are using
    var excelType = "Excel 8.0";
    if (excelFilename.Contains(".xlsx"))
    {
        excelType = "Excel 12.0 XML";
    }

    // 
    var connectionStringFormat = ConfigurationManager.AppSettings["Microsoft.ACE.OLEDB"].ToString();
    var excelNamePath = string.Format(@"{0}\{1}", Environment.CurrentDirectory, excelFilename);
    var connectionString = string.Format(connectionStringFormat, excelNamePath, excelType);

    // Create a connection to the excel file
    using (var oleDbConnection = new OleDbConnection(connectionString))
    {
        // Get the excel's sheet names
        oleDbConnection.Open();
        var schemaDataTable = (DataTable)oleDbConnection.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
        oleDbConnection.Close();
        var sheetsName = GetSheetsName(schemaDataTable);

        // For each sheet name 
        OleDbCommand selectCommand = null;
        for (var i = 0; i < sheetsName.Count; i++)
        {
            // Setup select command
            selectCommand = new OleDbCommand();
            selectCommand.CommandText = "SELECT * FROM [" + sheetsName[i] + "]";
            selectCommand.Connection = oleDbConnection;

            // Get the data from the sheet
            oleDbConnection.Open();
            using (var oleDbDataReader = selectCommand.ExecuteReader(CommandBehavior.CloseConnection))
            {
                // Convert data to DataTable
                var dataTable = new DataTable(sheetsName[i].Replace("$", "").Replace("'", ""));
                dataTable.Load(oleDbDataReader);

                // Add to Dataset
                dataSet.Tables.Add(dataTable);
            }
        }

        return dataSet;
    }
}

private List GetSheetsName(DataTable schemaDataTable)
{
    var sheets = new List();
    foreach(var dataRow in schemaDataTable.AsEnumerable())
    {
        sheets.Add(dataRow.ItemArray[2].ToString());
    }

    return sheets;
}