ADO.NET :: How To Replace The Field Names In SQL Query String With Variables

How can I replace the field names in sql query string with variables like:-

string field1="ID";
string field2="Name";
sql = "Insert into [Sheet1$] ('" + field1 + "','" + field2 + "') values('1','abc')";

I am inserting data into an Excel document which has got nearly 100 columns.

I am inserting data using OLEDB as follows:-

System.Data.OleDb.OleDbConnection MyConnection ;
System.Data.OleDb.OleDbCommand myCommand = new System.Data.OleDb.OleDbCommand();
string sql = null;
MyConnection = new System.Data.OleDb.OleDbConnection(connectionstring);
MyConnection.Open();
myCommand.Connection = MyConnection;
sql = "Insert into [Sheet1$] (ID,Name) values('1','abc')";
myCommand.CommandText = sql;
myCommand.ExecuteNonQuery();
MyConnection.Close();

I want to specify the field names at runtime as mentioned above - sql = "Insert into [Sheet1$] ('" + field1 + "','" + field2 + "') values('1','abc')"; When I try this I am getting error.