【C#公共帮助类】 Convert帮助类

大家知道，开发项目除了数据访问层很重要外，就是Common了，这里就提供了强大且实用的工具。

【C#公共帮助类】 Image帮助类

一、DataTable

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Reflection;
using System.Collections;

namespace Common
{
    public partial class DataTable
    {
        /// <summary>
        /// 转换 DataTable 对象为 IList 对象
        /// </summary>
        /// <param name="datas">数据集合</param>
        /// <returns>数组对象</returns>
        public static T[] ToArray<T>(DataTable datas) where T : class, new()
        {
            List<T> list = ToList<T>(datas) as List<T>;
            return list.ToArray();
        }

        /// <summary>
        /// 转换IList对象为DataTable对象
        /// </summary>
        /// <param name="datas">数据集合</param>
        /// <returns>DataTable对象</returns>
        public static DataTable ToDataTable<T>(IList<T> datas)
        {
            return ToDataTable<T>(datas, null);
        }

        /// <summary>
        /// 转换IList对象为DataTable对象
        /// </summary>
        /// <param name="datas">数据集合</param>
        /// <returns>DataTable对象</returns>
        public static DataTable ToDataTable<T>(T[] datas)
        {
            return ToDataTable<T>(datas, null);
        }

        /// <summary>
        /// 转换IList对象为DataTable对象
        /// </summary>
        /// <param name="datas">数据集合</param>
        /// <param name="tableName">要创建的表名</param>
        /// <returns>DataTable对象</returns>
        public static DataTable ToDataTable<T>(IList<T> datas, string tableName)
        {
            Type type = typeof(T);
            if (string.IsNullOrEmpty(tableName))
            {
                tableName = type.Name;
            }
            DataTable table = new DataTable(tableName);
            table.BeginLoadData();
            PropertyInfo[] properties = type.GetProperties(BindingFlags.Public | BindingFlags.Instance);
            foreach (PropertyInfo info in properties)
            {
                string typeName = info.PropertyType.ToString();
                if (info.PropertyType.IsGenericType)
                {
                    typeName = info.PropertyType.GetGenericArguments()[0].ToString();
                }
                Type type2 = Type.GetType(typeName, false);
                if (type2 != null)
                {
                    table.Columns.Add(info.Name, type2);
                }
            }
            if ((datas != null) && (datas.Count > 0))
            {
                foreach (object obj2 in datas)
                {
                    DataRow row = table.NewRow();
                    foreach (PropertyInfo info2 in properties)
                    {
                        if ((Type.GetType(info2.PropertyType.ToString(), false) != null) && (info2.GetValue(obj2, null) != null))
                        {
                            row[info2.Name] = info2.GetValue(obj2, null);
                        }
                    }
                    table.Rows.Add(row);
                }
            }
            table.EndLoadData();
            table.AcceptChanges();
            return table;
        }

        public static DataTable ListToDataTable(object datas, string tableName)
        {
            Type type = ZGeneric.GetGenericType(datas);
            if (string.IsNullOrEmpty(tableName))
                tableName = type.Name;

            DataTable table = new DataTable(tableName);
            table.BeginLoadData();

            var properties = ZReflection.GetProperties(type);
            foreach (var p in properties)
            {
                Type colType = p.Value.PropertyType;
                string typeName = colType.ToString();
                if (colType.IsGenericType)
                    typeName = colType.GetGenericArguments()[0].ToString();

                Type newType = Type.GetType(typeName, false);
                if (newType != null)
                    table.Columns.Add(p.Value.Name, newType);
            }

            IEnumerator enumerator = ((dynamic)datas).GetEnumerator();
            while (enumerator.MoveNext())
            {
                DataRow row = table.NewRow();
                foreach (var p in properties)
                {
                    var value = ZGeneric.GetValue(enumerator.Current, p.Value.Name);
                    if ((Type.GetType(p.Value.PropertyType.ToString(), false) != null) && (value != null))
                        row[p.Value.Name] = value;
                }
                table.Rows.Add(row);
            }
            table.EndLoadData();
            table.AcceptChanges();
            return table;
        }

        /// <summary>
        /// 转换IList对象为DataTable对象
        /// </summary>
        /// <param name="datas">数据集合</param>
        /// <param name="tableName">要创建的表名</param>
        /// <returns>DataTable对象</returns>
        public static DataTable ToDataTable<T>(T[] datas, string tableName)
        {
            IList<T> list;
            if ((datas == null) || (datas.Length == 0))
            {
                list = new List<T>();
            }
            else
            {
                list = new List<T>(datas);
            }
            return ToDataTable<T>(list, tableName);
        }

        /// <summary>
        /// 转换 DataTable 对象为 IList 对象
        /// </summary>
        /// <param name="datas">数据集合</param>
        /// <returns>IList 对象</returns>
        public static IList<T> ToList<T>(DataTable datas) where T : class, new()
        {
            IList<T> list = new List<T>();
            if ((datas != null) && (datas.Rows.Count != 0))
            {
                PropertyInfo[] properties = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);
                foreach (DataRow row in datas.Rows)
                {
                    T local = Activator.CreateInstance<T>();
                    foreach (DataColumn column in datas.Columns)
                    {
                        object obj2 = null;
                        if (row.RowState == DataRowState.Deleted)
                        {
                            obj2 = row[column, DataRowVersion.Original];
                        }
                        else
                        {
                            obj2 = row[column];
                        }
                        if (obj2 != DBNull.Value)
                        {
                            foreach (PropertyInfo info in properties)
                            {
                                if (column.ColumnName.Equals(info.Name, StringComparison.CurrentCultureIgnoreCase))
                                {
                                    info.SetValue(local, obj2, null);
                                }
                            }
                        }
                    }
                    list.Add(local);
                }
            }
            return list;
        }
    }
}

二、Enum

 public static T ToEnum<T>(object obj, T defaultEnum)
        {
            string str = To<string>(obj);

            if (Enum.IsDefined(typeof(T),str))
                return (T)Enum.Parse(typeof(T),str);

            int num;
            if (int.TryParse(str, out num))
            {
                if (Enum.IsDefined(typeof(T), num))
                    return (T)Enum.ToObject(typeof(T), num);
            }

            return defaultEnum;
        }

三、Generics

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections.Specialized;
using System.Reflection;

namespace Common
{
    public partial class Generics
    {
        /// <summary>
        /// 转换object为 T 值
        /// </summary>
        /// <typeparam name="T">T 类型</typeparam>
        /// <param name="obj">要被转换的值</param>
        /// <returns>T 类型值</returns>
        public static T To<T>(object obj)
        {
            return To<T>(obj, default(T));
        }

        /// <summary>
        /// 转换object为 T 值
        /// </summary>
        /// <typeparam name="T">T 类型</typeparam>
        /// <param name="obj">要被转换的值</param>
        /// <returns>T 类型值</returns>
        public static T To<T>(object obj,T defaultValue)
        {
            if (obj==null)
            {
                return defaultValue;
            }
            else if (obj is T)
            {
                return (T)obj;
            }
            else
            {
                try
                {
                    Type conversionType = typeof(T);
                    object obj2 = null;
                    if (conversionType.Equals(typeof(Guid)))
                        obj2 = new Guid(Convert.ToString(obj));
                    else
                        obj2 = Convert.ChangeType(obj, conversionType);
                    return (T)obj2;
                }
                catch (Exception)
                {
                    return defaultValue;
                }
            }
        }

        /// <summary>
        /// 填充客户端提交的值到 T 对象  如appinfo = AppConvert.To<Appinfo>(context.Request.Form);
        /// </summary>
        /// <typeparam name="T">T 类</typeparam>
        /// <param name="datas">客户端提交的值</param>
        /// <returns>T 对象</returns>
        public static T To<T>(NameValueCollection datas) where T : class, new()
        {
            Type type = typeof(T);
            string[] strArray = type.FullName.Split(new char[] { ‘.‘ });
            string str = strArray[strArray.Length - 1];
            PropertyInfo[] properties = type.GetProperties(BindingFlags.Public | BindingFlags.Instance);
            T local = Activator.CreateInstance<T>();
            foreach (string str2 in datas.AllKeys)
            {
                string str3 = datas[str2];
                if (!string.IsNullOrEmpty(str3))
                {
                    str3 = str3.TrimEnd(new char[0]);
                }
                foreach (PropertyInfo info in properties)
                {
                    string str4 = string.Format("{0}.{1}", str, info.Name);
                    if (str2.Equals(info.Name, StringComparison.CurrentCultureIgnoreCase) || str2.Equals(str4, StringComparison.CurrentCultureIgnoreCase))
                    {
                        string typeName = info.PropertyType.ToString();
                        if (info.PropertyType.IsGenericType)
                        {
                            typeName = info.PropertyType.GetGenericArguments()[0].ToString();
                        }
                        object nullInternal = GetNullInternal(info.PropertyType);
                        Type conversionType = Type.GetType(typeName, false);
                        if (!string.IsNullOrEmpty(str3))
                        {
                            nullInternal = Convert.ChangeType(str3, conversionType);
                        }
                        info.SetValue(local, nullInternal, null);
                    }
                }
            }
            return local;
        }

        #region 获取类型的默认值
        //另一种获取默认值的方法
        private static object GetDefaultValue(Type type)
        {
            object value = null;

            if (type.IsValueType)
                value = Activator.CreateInstance(type);
            else
                value = null;

            return value;
        }

        // 获取指定类型的默认值.引用类型(包含String)的默认值为null
        private static T DefaultValue<T>()
        {
            return default(T);
        }

        //获取默认值
        private static object GetNullInternal(Type type)
        {
            if (type.IsValueType)
            {
                if (type.IsEnum)
                {
                    return GetNullInternal(Enum.GetUnderlyingType(type));
                }
                if (type.IsPrimitive)
                {
                    if (type == typeof(int))
                    {
                        return 0;
                    }
                    if (type == typeof(double))
                    {
                        return 0.0;
                    }
                    if (type == typeof(short))
                    {
                        return (short)0;
                    }
                    if (type == typeof(sbyte))
                    {
                        return (sbyte)0;
                    }
                    if (type == typeof(long))
                    {
                        return 0L;
                    }
                    if (type == typeof(byte))
                    {
                        return (byte)0;
                    }
                    if (type == typeof(ushort))
                    {
                        return (ushort)0;
                    }
                    if (type == typeof(uint))
                    {
                        return 0;
                    }
                    if (type == typeof(ulong))
                    {
                        return (ulong)0L;
                    }
                    if (type == typeof(ulong))
                    {
                        return (ulong)0L;
                    }
                    if (type == typeof(float))
                    {
                        return 0f;
                    }
                    if (type == typeof(bool))
                    {
                        return false;
                    }
                    if (type == typeof(char))
                    {
                        return ‘\0‘;
                    }
                }
                else
                {
                    if (type == typeof(DateTime))
                    {
                        return DateTime.MinValue;
                    }
                    if (type == typeof(decimal))
                    {
                        return 0M;
                    }
                    if (type == typeof(Guid))
                    {
                        return Guid.Empty;
                    }
                    if (type == typeof(TimeSpan))
                    {
                        return new TimeSpan(0, 0, 0);
                    }
                }
            }
            return null;
        }
        #endregion
    }
}

四、String

 　　　　/// <summary>
        /// 转换为string类型 defult为string.Empty
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public static string ToString(object obj)
        {
             return To<string>(obj,string.Empty);
        }

五、TreeData

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Dynamic;

namespace Common
{
    public partial class TreeData
    {
        public static List<dynamic> ListToTreeData<T>(List<T> source, string ID, string PID) where T : class, new()
        {
            Action<List<dynamic>, T, dynamic> AddItem = (parent, item, Recursive) =>
            {
                var childrens = new List<dynamic>();
                var thisitem = ZGeneric.GetDictionaryValues(item);

                source.FindAll(o => ZGeneric.GetValue(item, ID).Equals(ZGeneric.GetValue(o, PID)))
                      .ForEach(subitem => { Recursive(childrens, subitem, Recursive); });

                thisitem.Add("children", childrens);
                parent.Add(thisitem);
            };

            var target = new List<dynamic>();
            source.FindAll(m => { return !source.Exists(n => ZGeneric.GetValue(n, ID).Equals(ZGeneric.GetValue(m, PID))); })
                  .ForEach(item => AddItem(target, item, AddItem));

            return target;
        }

        public static List<T> TreeDataToList<T>(List<dynamic> source)
        {
            Action<List<dynamic>, List<T>, dynamic> AddItem = (mysource, mytarget, Recursive) =>
            {
                foreach (var oldrow in mysource)
                {
                    var newrow = ZGeneric.CreateNew<T>();
                    var dictionary = (IDictionary<string, object>)ZGeneric.GetDictionaryValues(oldrow);

                    var childern = dictionary["childern"] as List<dynamic>;
                    if (childern.Count > 0) Recursive(mysource, mytarget, Recursive);

                    foreach (var property in dictionary)
                        if (property.Key != "children")
                            ZGeneric.SetValue(newrow, property.Key, property.Value);

                    mytarget.Add(newrow);
                }
            };

            var target = new List<T>();
            AddItem(source, target, AddItem);

            return target;
        }
    }
}