bnhtrade/src/bnhtrade.Core/Data/Database/SqlWhereBuilder.cs

using System;
using System.Collections.Generic;
using Microsoft.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace bnhtrade.Core.Data.Database
{
    /// <summary>
    /// Step 1: Call the methods for each where clause you want to create. This can be done multiple times to create an sql where string. Pay attention
    /// to the prefixes that you'll require between each where clause, as each time a method is called the sql statement will be appended to the previous sql 
    /// string.
    /// Step 2: Appened the created sql string to your sql statement, NB the WHERE statemet is not included by default.
    /// Step 3: Once you've created your sql command object, add the parameters to it using the method contained within this class.
    /// STep 4: exceute your sql commend.
    /// </summary>
    public class SqlWhereBuilder
    {
        private int parameterCount = 0;

        public SqlWhereBuilder()
        {
            Init();
        }

        public string SqlWhereString { get; private set; }

        public bool IsSetSqlWhereString
        {
            get
            {
                if (SqlWhereString == null || string.IsNullOrEmpty(SqlWhereString))
                {
                    return false;
                }
                else
                {
                    return true;
                }
            }
        }

        public Dictionary<string, object> ParameterList { get; private set; }

        /// <summary>
        /// Initialises the class
        /// </summary>
        public void Init()
        {
            parameterCount = 0;
            SqlWhereString = "";
            ParameterList = new Dictionary<string, object>();
        }

        public void AddParametersToSqlCommand(SqlCommand cmd)
        {
            if (ParameterList != null)
            {
                foreach (var item in ParameterList)
                {
                    cmd.Parameters.AddWithValue(item.Key, item.Value);
                }
            }
        }

        /// <summary>
        /// Append an 'In' statement and parameter list to the class properties
        /// </summary>
        /// <param name="columnReference">Name of the column to used to for the condition statement</param>
        /// <param name="orValueList">List of values to test in condition statement</param>
        /// <param name="wherePrefix">Optional prefix that gets added to the sql string result</param>
        public void In(string columnReference, List<string> orValueList, string wherePrefix = null)
        {
            if (orValueList == null || !orValueList.Any())
            {
                return;
            }

            var distinctList = orValueList.Distinct().ToList();

            string sqlWhere = @"
                ";

            if (wherePrefix != null)
            {
                sqlWhere += wherePrefix;
            }

            sqlWhere += " " + columnReference + " IN ( ";

            int listCount = distinctList.Count();
            for (int i = 0; i < listCount; i++, parameterCount++)
            {
                if (i > 0)
                {
                    sqlWhere += ", ";
                }

                string param = "@parameter" + parameterCount;
                sqlWhere += param;
                ParameterList.Add(param, distinctList[i]);
            }
            sqlWhere += " ) ";

            SqlWhereString = SqlWhereString + sqlWhere;
        }

        /// <summary>
        /// Append an 'In' statement and parameter list to the class properties
        /// </summary>
        /// <param name="columnReference">Name of the column to used to for the condition statement</param>
        /// <param name="orValueList">List of values to test in condition statement</param>
        /// <param name="wherePrefix">Optional prefix that gets added to the sql string result</param>
        public void In(string columnReference, List<int> orValueList, string wherePrefix = null)
        {
            var stringList = new List<string>();

            if (orValueList != null || !orValueList.Any())
            {
                foreach (int value in orValueList)
                {
                    stringList.Add(value.ToString());
                }
            }

            In(columnReference, stringList, wherePrefix);
        }
    }
}