C# List与DataTable的相互转化

List与Data的转化比较简单，网上也很多。但是大多都有一个Bug：当实体类有可空类型的属性时，转化会出异常（DATASET不支持System.Nullable异常）

下面的方法可以避免出现这个问题。

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①List转DataTable

#region  反射List To DataTable
/// <summary>  
/// 将集合类转换成DataTable  
/// </summary>  
/// <param name="list">集合</param>  
/// <returns></returns>  
public static DataTable ListToDataTable(IList list)
{
    DataTable result = new DataTable();
    if (list.Count > 0)
    {
        PropertyInfo[] propertys = list[0].GetType().GetProperties();

        foreach (PropertyInfo pi in propertys)
        {
            Type colType = pi.PropertyType;
            if ((colType.IsGenericType) && (colType.GetGenericTypeDefinition() == typeof(Nullable<>)))
            {
                colType = colType.GetGenericArguments()[0];
            }
            result.Columns.Add(new DataColumn(pi.Name, colType));
        }

        for (int i = 0; i < list.Count; i++)
        {
            ArrayList tempList = new ArrayList();
            foreach (PropertyInfo pi in propertys)
            {
                object obj = pi.GetValue(list[i], null);
                tempList.Add(obj);
            }
            object[] array = tempList.ToArray();
            result.LoadDataRow(array, true);
        }
    }
    return result;
} 

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