这是我的C#代码
Employee objEmp = new Employee();
List<Employee> empList = new List<Employee>();
foreach (DataRow dr in ds.Tables[0].Rows)
{
empList.Add(new Employee { Name = Convert.ToString(dr["Name"]), Age = Convert.ToInt32(dr["Age"]) });
}
它使用循环从数据集创建一个列表。是否有任何直接方法、更短的方法或一行代码将数据集转换为列表？
尝试使用类似以下的代码：
var empList = ds.Tables[0].AsEnumerable()
.Select(dataRow => new Employee
{
Name = dataRow.Field<string>("Name")
}).ToList();
public static class Extensions
{
public static List<T> ToList<T>(this DataTable table) where T : new()
{
IList<PropertyInfo> properties = typeof(T).GetProperties().ToList();
List<T> result = new List<T>();
foreach (var row in table.Rows)
{
var item = CreateItemFromRow<T>((DataRow)row, properties);
result.Add(item);
}
return result;
}
private static T CreateItemFromRow<T>(DataRow row, IList<PropertyInfo> properties) where T : new()
{
T item = new T();
foreach (var property in properties)
{
if (property.PropertyType == typeof(System.DayOfWeek))
{
DayOfWeek day = (DayOfWeek)Enum.Parse(typeof(DayOfWeek), row[property.Name].ToString());
property.SetValue(item,day,null);
}
else
{
if(row[property.Name] == DBNull.Value)
property.SetValue(item, null, null);
else
{
if (Nullable.GetUnderlyingType(property.PropertyType) != null)
{
//nullable
object convertedValue = null;
try
{
convertedValue = System.Convert.ChangeType(row[property.Name], Nullable.GetUnderlyingType(property.PropertyType));
}
catch (Exception ex)
{
}
property.SetValue(item, convertedValue, null);
}
else
property.SetValue(item, row[property.Name], null);
}
}
}
return item;
}
}
使用方法：
List<Employee> lst = ds.Tables[0].ToList<Employee>();
@itay.b
代码解释：
我们首先使用反射从类T中读取所有属性名称，
然后我们遍历datatable中的所有行，并创建T类的新对象，
接着，我们使用反射设置新创建对象的属性。
属性值来自行匹配列单元格的值。
注意：类属性名称和表列名称必须相同。
CreateItemFromRow 中，为什么首先要检查属性的类型是否等于 typeof(System.DayOfWeek)？调用 property.SetValue(item, row[property.Name], null) 会引发异常吗？ - Steven Volckaertvar myData = ds.Tables[0].AsEnumerable().Select(r => new Employee {
Name = r.Field<string>("Name"),
Age = r.Field<int>("Age")
});
var list = myData.ToList(); // For if you really need a List and not IEnumerable
using Newtonsoft.Json;
string JSONString = string.Empty;
JSONString = JsonConvert.SerializeObject(ds.Tables[0]);
DataSet ds = new DataSet();
ds = obj.getXmlData();// get the multiple table in dataset.
Employee objEmp = new Employee ();// create the object of class Employee
List<Employee > empList = new List<Employee >();
int table = Convert.ToInt32(ds.Tables.Count);// count the number of table in dataset
for (int i = 1; i < table; i++)// set the table value in list one by one
{
foreach (DataRow dr in ds.Tables[i].Rows)
{
empList.Add(new Employee { Title1 = Convert.ToString(dr["Title"]), Hosting1 = Convert.ToString(dr["Hosting"]), Startdate1 = Convert.ToString(dr["Startdate"]), ExpDate1 = Convert.ToString(dr["ExpDate"]) });
}
}
dataGridView1.DataSource = empList;
尝试这个... 根据您的需求修改代码。
List<Employee> target = dt.AsEnumerable()
.Select(row => new Employee
{
Name = row.Field<string?>(0).GetValueOrDefault(),
Age= row.Field<int>(1)
}).ToList();
public static class Helper
{
public static List<T> DataTableToList<T>(this DataTable table) where T : class, new()
{
try
{
List<T> list = new List<T>();
foreach (var row in table.AsEnumerable())
{
T obj = new T();
foreach (var prop in obj.GetType().GetProperties())
{
try
{
PropertyInfo propertyInfo = obj.GetType().GetProperty(prop.Name);
propertyInfo.SetValue(obj, Convert.ChangeType(row[prop.Name], propertyInfo.PropertyType), null);
}
catch
{
continue;
}
}
list.Add(obj);
}
return list;
}
catch
{
return null;
}
}
}
在您的代码后台中可以像下面这样访问此类：
DataTable dtt = dsCallList.Tables[0];
List<CallAssignment> lstCallAssignement = dtt.DataTableToList<CallAssignment>();
我无法让Nitin Sawant的答案起作用，但我能够修改他的代码以适应我的需求。实际上，我需要使用GetRuntimeFields而不是GetProperties。这就是我最终得到的代码：
public static class Extensions
{
public static List<T> ToList<T>(this DataTable table) where T : new()
{
IList<FieldInfo> fields = typeof(T).GetRuntimeFields().ToList();
List<T> result = new List<T>();
if (row.Table.Columns.Contains(field.Name))
{
foreach (var row in table.Rows)
{
var item = CreateItemFromRow<T>((DataRow)row, fields);
result.Add(item);
}
}
return result;
}
private static T CreateItemFromRow<T>(DataRow row, IList<FieldInfo> fields) where T : new()
{
T item = new T();
foreach (var field in fields)
{
if (row[field.Name] == DBNull.Value)
field.SetValue(item, null);
else
field.SetValue(item, row[field.Name]);
}
return item;
}
}
List<T> result = new List<T>();这一行后面你忘记了使用foreach循环。 - Burak Dobur从存储过程命令中填充数据集
DbDataAdapter adapter = DbProviderFactories.GetFactory(cmd.Connection).CreateDataAdapter();
adapter.SelectCommand = cmd;
DataSet ds = new DataSet();
adapter.Fill(ds);
string s = ds.GetXmlSchema();
xsd datasetSchema.xsd /c
public static T Create<T>(string xml)
{
XmlSerializer serializer = new XmlSerializer(typeof(T));
using (StringReader reader = new StringReader(xml))
{
T t = (T)serializer.Deserialize(reader);
reader.Close();
return t;
}
}
var xml = ds.GetXml();
var dataSetObjects = Create<NewDataSet>(xml);
public DataTable ListToDataTable<T>(IList<T> data)
{
PropertyDescriptorCollection props =
TypeDescriptor.GetProperties(typeof(T));
DataTable table = new DataTable();
for (int i = 0; i < props.Count; i++)
{
PropertyDescriptor prop = props[i];
table.Columns.Add(prop.Name, prop.PropertyType);
}
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);
}
return table;
}