Everyday type conversion-ClassHelper
一、DataTable与实体类互相转换
二、Databale于List<T>相互转换
public static class ConvertHelper<T> where T : new()
{
/// <summary>
/// 利用反射和泛型
/// </summary>
/// <param name="dt"></param>
/// <returns></returns>
public static List<T> ConvertToList(DataTable dt)
{
List<T> ts = new List<T>();// 定义集合
Type type = typeof(T);// 获得此模型的类型
string tempName = string.Empty;//定义一个临时变量
foreach (DataRow dr in dt.Rows) //遍历DataTable中所有的数据行
{
T t = new T(); // 获得此模型的公共属性
PropertyInfo[] propertys = t.GetType().GetProperties();
foreach (PropertyInfo pi in propertys)//遍历该对象的所有属性
{
tempName = pi.Name;//将属性名称赋值给临时变量
if (dt.Columns.Contains(tempName))//检查DataTable是否包含此列（列名==对象的属性名）
{
// 判断此属性是否有Setter
if (!pi.CanWrite) continue;//该属性不可写，直接跳出
//取值object value = dr[tempName];
if (value != DBNull.Value) //如果非空，则赋给对象的属性
pi.SetValue(t, TypeConversion.GetDataType(pi, value.ToString()), null);
}
}
ts.Add(t); //对象添加到泛型集合中
}
return ts;
}
}
/// <summary>
/// 功能说明： 将一个列表转换成DataTable,如果列表为空将返回空的DataTable结构
/// 创建人：卜发相
/// 创建日期：2012-4-22
/// </summary>
/// <typeparam name="T">要转换的数据类型</typeparam>
/// <param name="entityList">实体对象列表</param>
public static DataTable EntityListToDataTable<T>(List<T> entityList)
{
DataTable dt = new DataTable();
//取类型T所有Propertie
Type entityType = typeof(T);
PropertyInfo[] entityProperties = entityType.GetProperties();
Type colType = null;
foreach (PropertyInfo propInfo in entityProperties)
{
if (propInfo.PropertyType.IsGenericType)
{
colType = Nullable.GetUnderlyingType(propInfo.PropertyType);
}
else
{
colType = propInfo.PropertyType;
}
if (colType.FullName.StartsWith("System"))
{
if (!propInfo.IsDefined(typeof(CloudCall.MODEL.PKAttribute), false))
{
dt.Columns.Add(propInfo.Name, colType);
}
}
}
if (entityList != null && entityList.Count > 0)
{
foreach (T entity in entityList)
{
DataRow newRow = dt.NewRow();
foreach (PropertyInfo propInfo in entityProperties)
{
if (dt.Columns.Contains(propInfo.Name))
{
object objValue = propInfo.GetValue(entity, null);
newRow[propInfo.Name] = objValue == null ? DBNull.Value : objValue; } } dt.Rows.Add(newRow);
}
}
return dt;
}
三、DataSet于JSON互相转换
public class DataJson {
/// <summary>
/// 将JSON转化成DataSet数据
/// </summary>
/// <param name="ds"></param>
/// <returns></returns>
public static DataSet JsonToDataSet(string Json)
{
try
{
DataSet ds = new DataSet(); J
avaScriptSerializer JSS = new JavaScriptSerializer();
object obj = JSS.DeserializeObject(Json);
Dictionary<string, object> datajson = (Dictionary<string, object>)obj;
foreach (var item in datajson)
{
DataTable dt = new DataTable(item.Key);
object[] rows = (object[])item.Value;
foreach (var row in rows)
{
Dictionary<string, object> val = (Dictionary<string, object>)row;
DataRow dr = dt.NewRow();
foreach (KeyValuePair<string, object> sss in val)
{
if (!dt.Columns.Contains(sss.Key))
{
dt.Columns.Add(sss.Key.ToString());
dr[sss.Key] = sss.Value;
}
else
dr[sss.Key] = sss.Value;
}
dt.Rows.Add(dr);
}
ds.Tables.Add(dt);
}
return ds;
}
catch
{
return null;
}
}
/// <summary>
/// 将DataSet转化成JSON数据
/// </summary>
/// <param name="ds"></param>
/// <returns></returns>
public static string DataSetToJson(DataSet ds)
{
string json = string.Empty;
try
{
if (ds.Tables.Count == 0)
throw new Exception("DataSet中Tables为0");
json = "{";
for (int i = 0; i < ds.Tables.Count; i++)
{
json += "T" + (i + 1) + ":[";
for (int j = 0; j < ds.Tables[i].Rows.Count; j++)
{
json += "{";
for (int k = 0; k < ds.Tables[i].Columns.Count; k++)
{
json += ds.Tables[i].Columns[k].ColumnName + ":'" + ds.Tables[i].Rows[j][k].ToString() + "'";
if (k != ds.Tables[i].Columns.Count - 1)
json += ",";
}
json += "}";
if (j != ds.Tables[i].Rows.Count - 1)
json += ",";
}
json += "]";
if (i != ds.Tables.Count - 1)
json += ",";
}
json += "}";
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
return json;
}
}
}
四、以上转换中的值类型转换(Table于List<T>互相转换必须引用)
#region 类型转换
#region 转换当前遍历到的数据类型填充到对应对象 + public object GteDataTypes(PropertyInfo property, string value)
/// <summary>
/// 功能说明：转换当前遍历到的数据类型填充到对应对象；
/// 创建人：卜发相
/// 创建日期：2012-5-10
/// </summary>
/// <param name="property"></param>
/// <param name="value">值</param>
/// <returns></returns>
public object GteDataTypes(PropertyInfo property, string value)
{
string proName = property.PropertyType.FullName;
if (value == "")
{
return null;
}
else
{
if (proName.Contains("Int32"))
{
return Convert.ToInt32(value);
}
else if (proName.Contains("String"))
{
return Convert.ToString(value);
}
else if (proName.Contains("DateTime"))
{
return Convert.ToDateTime(value);
}
else if (proName.Contains("Boolean"))
{
return Convert.ToBoolean(value);
}
else if (proName.Contains("System.Guid"))
{
return new System.Guid(value);
}
else
{
return null;
}
}
}
#endregion
#region 获取当前属性元数据的类型+private Type GetDataType(PropertyInfo property)
/// <summary>
/// 功能说明：获取当前属性元数据的类型；
/// 创建人：袁源
/// 创建日期：2012-4-20
/// </summary>
/// <param name="property"></param>
/// <returns>Type</returns>
public Type GetDataType(PropertyInfo property)
{
string proName = property.PropertyType.FullName;
if (proName.Contains("Int32"))
{
return typeof(int);
}
else if (proName.Contains("String"))
{
return typeof(string);
}
else if (proName.Contains("DateTime"))
{
return typeof(DateTime);
}
else if (proName.Contains("Boolean"))
{
return typeof(bool);
}
else if (proName.Contains("System.Guid"))
{
return typeof(System.Guid);
}
else
{
return null;
}
}
#endregion
#endregion
}
