DataTable 與 Entity 間的轉換工具

做個筆記，改了改代碼，今後在項目中會常用到

DataTableEntityConverter

using System;using System.Collections.Generic;using System.Text;using System.Data;using System.Reflection;using System.ComponentModel;namespace Utils{    public static class DataTableEntityConverter    {        public static T ConvertToEntity<T>(DataRow tableRow) where T : new()        {            // Create a new type of the entity I want            Type t = typeof(T);            T returnObject = new T();            foreach (DataColumn col in tableRow.Table.Columns)            {                string colName = col.ColumnName;                // Look for the object's property with the columns name, ignore case                PropertyInfo pInfo = t.GetProperty(colName.ToLower(),                    BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);                // did we find the property ?                if (pInfo != null)                {                    object val = tableRow[colName];                    // is this a Nullable<> type                    bool IsNullable = (Nullable.GetUnderlyingType(pInfo.PropertyType) != null);                    if (IsNullable)                    {                        if (val is System.DBNull)                        {                            val = null;                        }                        else                        {                            // Convert the db type into the T we have in our Nullable<T> type                            val = Convert.ChangeType(val, Nullable.GetUnderlyingType(pInfo.PropertyType));                        }                    }                    else                    {                        try                        {                            // Convert the db type into the type of the property in our entity                            val = Convert.ChangeType(val, pInfo.PropertyType);                        }                        catch (Exception)                        {                        }                    }                    try                    {                        // Set the value of the property with the value from the db                        pInfo.SetValue(returnObject, val, null);                    }                    catch (Exception)                    {                    }                }            }            // return the entity object with values            return returnObject;        }        public static List<T> ConvertToEntityList<T>(DataTable table) where T : new()        {            // Create a new type of the entity I want            List<T> result = new List<T>();            foreach (DataRow tableRow in table.Rows)            {                Type t = typeof(T);                T returnObject = new T();                foreach (DataColumn col in table.Columns)                {                    string colName = col.ColumnName;                    // Look for the object's property with the columns name, ignore case                    PropertyInfo pInfo = t.GetProperty(colName.ToLower(),                        BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);                    // did we find the property ?                    if (pInfo != null)                    {                        object val = tableRow[colName];                        // is this a Nullable<> type                        bool IsNullable = (Nullable.GetUnderlyingType(pInfo.PropertyType) != null);                        if (IsNullable)                        {                            if (val is System.DBNull)                            {                                val = null;                            }                            else                            {                                // Convert the db type into the T we have in our Nullable<T> type                                val = Convert.ChangeType                        (val, Nullable.GetUnderlyingType(pInfo.PropertyType));                            }                        }                        else                        {                            // Convert the db type into the type of the property in our entity                            val = Convert.ChangeType(val, pInfo.PropertyType);                        }                        // Set the value of the property with the value from the db                        pInfo.SetValue(returnObject, val, null);                    }                }                result.Add(returnObject);            }            // return the entity object with values            return result;        }        public static DataTable GetDataTableSchema<T>()        {            PropertyDescriptorCollection props =                           TypeDescriptor.GetProperties(typeof(T));            DataTable table = new DataTable();            for (int i = 0; i < props.Count; i++)            {                PropertyDescriptor prop = props[i];                Type pt = prop.PropertyType;                if (pt.IsGenericType && pt.GetGenericTypeDefinition() == typeof(Nullable<>))                    pt = Nullable.GetUnderlyingType(pt);                table.Columns.Add(prop.Name, pt);            }            return table;        }        public static DataTable ConvertToDataTable<T>(List<T> data)        {            PropertyDescriptorCollection props =                           TypeDescriptor.GetProperties(typeof(T));            DataTable table = GetDataTableSchema<T>();            object[] values = new object[props.Count];            foreach (T item in data)            {                for (int i = 0; i < values.Length; i++)                {                    values[i] = props[i].GetValue(item);                }                table.Rows.Add(values);            }            table.AcceptChanges();            return table;        }    }}