title: How to do a mapping of an excel file using c#
body: <p>I wanted to do a mapping of an excel file but with the columns in a certain way.
  As for example I have an exel file where the second column (of the excel file) has to be referenced there is 1 column of the sql database.</p>
  
  <p>This is the <code>Form</code> I'm using:
  <a href="https://i.stack.imgur.com/IEyT8.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/IEyT8.png" alt="enter image description here"></a></p>
  
  <p>I already have the sql search done I just wanted to know how I can put in the combobox the name of the columns in the excel file.</p>
  
  <p>This is the code I am using to search the excel file:</p>
  
  <pre><code>        using (OpenFileDialog ofd = new OpenFileDialog() { Filter = "Excel Workbook|*.xls", ValidateNames = true })
          {
              DataSet result;
              if (ofd.ShowDialog() == DialogResult.OK)
              {
                  FileStream fs = File.Open(ofd.FileName, FileMode.Open, FileAccess.Read);
                  IExcelDataReader reader = ExcelReaderFactory.CreateBinaryReader(fs);
                  reader.IsFirstRowAsColumnNames = true;
                  result = reader.AsDataSet();
                  comboBox1.Items.Clear();
                  foreach (DataTable dt in result.Tables) comboBox1.Items.Add(dt.TableName);
                  reader.Close();
  
                  string ConecçãoDB = ConfigurationManager.ConnectionStrings["ConecçaoDB"].ConnectionString;
                  string Table = ConfigurationManager.AppSettings["table"];
  
                  string ssqltable = Table;
  
                  string ssqlconnectionstring = ConecçãoDB;
  
                  filename = ofd.FileName;
                  MessageBox.Show(Convert.ToString(filename));
                  var connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + filename + ";Extended Properties=\"Excel 12.0;IMEX=1;HDR=NO;TypeGuessRows=0;ImportMixedTypes=Text\"";
                  var conexao = new System.Data.OleDb.OleDbConnection(connectionString);
                  var sql = "SELECT * FROM [" + comboBox1.SelectedText + "$]";
                  string sclearsql = "delete from " + ssqltable;
              }
          }
  </code></pre>