C# 常用公共方法

8.DataTable转换成实体类

 /// <summary>
 /// #region DataTable转换成实体类
 /// </summary>
 /// <typeparam name="T"></typeparam>
 public class ModelUtil<T> where T : new()
 {

  /// <summary>
  /// 填充对象列表：用DataSet的第一个表填充实体类
  /// </summary>
  /// <param name="ds">DataSet</param>
  /// <returns></returns>
  public static List<T> FillModel(DataSet ds)
  {
   if (ds == null || ds.Tables[0] == null || ds.Tables[0].Rows.Count == 0)
   {
    return null;
   }
   else
   {
    return FillModel(ds.Tables[0]);
   }
  }

  /// <summary> 
  /// 填充对象列表：用DataSet的第index个表填充实体类
  /// </summary> 
  public static List<T> FillModel(DataSet ds, int index)
  {
   if (ds == null || ds.Tables.Count <= index || ds.Tables[index].Rows.Count == 0)
   {
    return null;
   }
   else
   {
    return FillModel(ds.Tables[index]);
   }
  }

  /// <summary> 
  /// 填充对象列表：用DataTable填充实体类
  /// </summary> 
  public static List<T> FillModel(DataTable dt)
  {
   if (dt == null || dt.Rows.Count == 0)
   {
    return null;
   }
   List<T> modelList = new List<T>();
   foreach (DataRow dr in dt.Rows)
   {
    //T model = (T)Activator.CreateInstance(typeof(T)); 
    T model = new T();
    for (int i = 0; i < dr.Table.Columns.Count; i++)
    {
     List<PropertyInfo> propertyInfos = model.GetType().GetProperties().ToList();

     PropertyInfo item = propertyInfos.FirstOrDefault(p => string.Compare(p.Name, dr.Table.Columns[i].ColumnName, true) == 0);
     if (item != null && dr[i] != DBNull.Value)
      try
      {
       item.SetValue(model, dr[i], null);
      }
      catch
      {
      }
    }

    modelList.Add(model);
   }
   return modelList;
  }

  /// <summary> 
  /// 填充对象：用DataRow填充实体类
  /// </summary> 
  public static T FillModel(DataRow dr)
  {
   if (dr == null)
   {
    return default(T);
   }

   //T model = (T)Activator.CreateInstance(typeof(T)); 
   T model = new T();

   for (int i = 0; i < dr.Table.Columns.Count; i++)
   {
    List<PropertyInfo> propertyInfos = model.GetType().GetProperties().ToList();

    PropertyInfo item = propertyInfos.FirstOrDefault(p => string.Compare(p.Name, dr.Table.Columns[i].ColumnName, true) == 0);
    if (item != null && dr[i] != DBNull.Value)
     try
     {
      item.SetValue(model, dr[i], null);
     }
     catch
     {
     }
   }
   return model;
  }


  /// <summary>
  /// 实体类转换成DataSet
  /// </summary>
  /// <param name="modelList">实体类列表</param>
  /// <returns></returns>
  public static DataSet FillDataSet(List<T> modelList)
  {
   if (modelList == null || modelList.Count == 0)
   {
    return null;
   }
   else
   {
    DataSet ds = new DataSet();
    ds.Tables.Add(FillDataTable(modelList));
    return ds;
   }
  }

  /// <summary>
  /// 实体类转换成DataTable
  /// </summary>
  /// <param name="modelList">实体类列表</param>
  /// <returns></returns>
  public static DataTable FillDataTable(List<T> modelList)
  {
   if (modelList == null || modelList.Count == 0)
   {
    return null;
   }
   DataTable dt = CreateData(modelList[0]);

   foreach (T model in modelList)
   {
    DataRow dataRow = dt.NewRow();
    foreach (PropertyInfo propertyInfo in typeof(T).GetProperties())
    {
     dataRow[propertyInfo.Name] = propertyInfo.GetValue(model, null);
    }
    dt.Rows.Add(dataRow);
   }
   return dt;
  }

  /// <summary>
  /// 根据实体类得到表结构
  /// </summary>
  /// <param name="model">实体类</param>
  /// <returns></returns>
  private static DataTable CreateData(T model)
  {
   DataTable dataTable = new DataTable(typeof(T).Name);
   foreach (PropertyInfo propertyInfo in typeof(T).GetProperties())
   {
    dataTable.Columns.Add(new DataColumn(propertyInfo.Name, propertyInfo.PropertyType));
   }
   return dataTable;
  }

  /// <summary>
  /// 将DataTable以转为List与Dictionary嵌套集合保存
  /// </summary>
  /// <param name="dt"></param>
  /// <returns></returns>
  public static List<Dictionary<string, string>> ToListDictionary(DataTable dt)
  {
   List<Dictionary<string, string>> list = null;
   if (dt != null && dt.Rows.Count > 0)
   {
    list = new List<Dictionary<string, string>>();
    Dictionary<string, string> dic = null;
    foreach (DataRow dr in dt.Rows)
    {
     dic = new Dictionary<string, string>();
     foreach (DataColumn dc in dt.Columns)
     {
      dic.Add(dc.ColumnName, dr[dc.ColumnName].ToString());
     }
     list.Add(dic);
    }
   }
   return list;
  }

  /// <summary>
  /// 请求的request的内容转换为model
  /// cza
  /// 2016-5-30 19:06:21
  /// </summary>
  /// <param name="context"></param>
  /// <returns></returns>
  public static T ConvertToModel(HttpContext context)
  {
   T t = new T();
   PropertyInfo[] propertys = t.GetType().GetProperties();
   foreach (PropertyInfo pi in propertys)
   {
    if (!pi.CanWrite)
     continue;
    object value = context.Request[pi.Name];
    if (value != null && value != DBNull.Value)
    {
     try
     {
      if (value.ToString() != "")
       pi.SetValue(t, Convert.ChangeType(value, pi.PropertyType), null);//这一步很重要，用于类型转换
      else
       pi.SetValue(t, value, null);
     }
     catch
     { }
    }
   }

   return t;
  }


 }

								 
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