Dynamic CAML Query in SharePoint programmatically

When we have to filter more than 2 column, it is very difficult to create CAML query. For example, our application have more than 2 drop down (Bind to SharePoint list column) as search criteria then it is difficult to generate CAML query. To create dynamic CAML query please check this code

class Program {
    public static string CreateCAMLQuery(List < string > parameters, string orAndCondition, bool isIncludeWhereClause) {
        StringBuilder sb = new StringBuilder();
        if (parameters.Count == 0) {
            AppendEQ(sb, "all");
        }
        int j = 0;
        for (int i = 0; i < parameters.Count; i++) {
            if (!string.IsNullOrEmpty(parameters[i].Split(';')[3])) {
                AppendEQ(sb, parameters[i]);
                if (i > 0 && j > 0) {
                    sb.Insert(0, "<" + orAndCondition + ">");
                    sb.Append("</" + orAndCondition + ">");
                }
                j++;
            }
        }
        if (isIncludeWhereClause) {
            sb.Insert(0, "<Where>");
            sb.Append("</Where>");
        }
        return sb.ToString();
    }
    public static void AppendEQ(StringBuilder sb, string value) {
        string[] field = value.Split(';');
        sb.AppendFormat("<{0}>", field[2].ToString());
        sb.AppendFormat("<FieldRef Name='{0}'/>", field[0].ToString());
        sb.AppendFormat("<Value Type='{0}'>{1}</Value>", field[1].ToString(), field[3].ToString());
        sb.AppendFormat("</{0}>", field[2].ToString());
    }
    static void Main(string[] args) {
        List < string > objColumns = new List < string > ();
        // here, format is like: "Column name(internal name of column);Column type; Conditional operator; Search string (input by user)
        objColumns.Add("Title;Text;Eq;" + "abc");
        objColumns.Add("FileLeafRef;Text;Eq;" + "PQR");
        objColumns.Add("DropDown;Text;Eq;" + "abc");
        objColumns.Add("FileLeafRef1;Text;Eq;" + "PQR");
        string query = CreateCAMLQuery(objColumns, "And", true);
        Console.WriteLine(query);
        Console.Read();
    }
}