Class DataTableExtensions

DataTable 扩展方法

Inheritance

Object

DataTableExtensions

Inherited Members

Object.Equals(Object)

Object.Equals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Object.ToString()

Namespace: Lett.Extensions

Assembly: Lett.Extensions.dll

Syntax

public static class DataTableExtensions

Fields

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SupportedDataTypes

DataTable 支持的数据类型

参考：https://docs.microsoft.com/zh-cn/dotnet/api/system.data.datacolumn.datatype?view=netcore-2.0

Declaration

public static readonly IReadOnlyList<Type> SupportedDataTypes

Field Value

Type	Description
IReadOnlyList<Type>

Methods

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ColumnsEnumerable(DataTable)

获取DataColumn可枚举对象

Declaration

public static IEnumerable<DataColumn> ColumnsEnumerable(this DataTable this)

Parameters

Type	Name	Description
DataTable	this

Returns

Type	Description
IEnumerable<DataColumn>

Examples

var rs = dataTable.ColumnsEnumerable();

Exceptions

Type	Condition
ArgumentNullException	DataColumn为空
InvalidCastException

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FirstRow(DataTable)

获取首行

Declaration

public static DataRow FirstRow(this DataTable this)

Parameters

Type	Name	Description
DataTable	this

Returns

Type	Description
DataRow

Examples

dataTable.FirstRow();

Exceptions

Type	Condition
ArgumentException	当前DataTable没有行

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GetColumnDataType(DataTable, Int32)

获取Column的数据类型

Declaration

public static Type GetColumnDataType(this DataTable this, int index)

Parameters

Type	Name	Description
DataTable	this
Int32	index	索引

Returns

Type	Description
Type

Examples

var columnType = dataTable.GetColumnDataType(-1);

Exceptions

Type	Condition
ArgumentOutOfRangeException	`index` 索引超出了数组范围

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GetColumnDataType(DataTable, String)

获取Column的数据类型

Declaration

public static Type GetColumnDataType(this DataTable this, string columnName)

Parameters

Type	Name	Description
DataTable	this
String	columnName	列名

Returns

Type	Description
Type

Examples

var columnType = dt.GetColumnDataType("columnName");

Exceptions

Type	Condition
ArgumentException	DataTable中不包含`columnName`

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HasRows(DataTable)

是否存在数据行

Declaration

public static bool HasRows(this DataTable this)

Parameters

Type	Name	Description
DataTable	this

Returns

Type	Description
Boolean

Examples

dataTable.HasRows();

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LastRow(DataTable)

获取末行

Declaration

public static DataRow LastRow(this DataTable this)

Parameters

Type	Name	Description
DataTable	this

Returns

Type	Description
DataRow

Examples

dataTable.LastRow();

Exceptions

Type	Condition
ArgumentException	当前DataTable没有行

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RowsEnumerable(DataTable)

获取DataRow可枚举对象

Declaration

public static IEnumerable<DataRow> RowsEnumerable(this DataTable this)

Parameters

Type	Name	Description
DataTable	this

Returns

Type	Description
IEnumerable<DataRow>

Examples

var rs = dataTable.RowsEnumerable();

Exceptions

Type	Condition
ArgumentNullException	DataRow 为空
InvalidCastException

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ToDynamicObjects(DataTable)

转换为动态对象集合

值为 Value 转换为 Null

Declaration

public static IEnumerable<dynamic> ToDynamicObjects(this DataTable this)

Parameters

Type	Name	Description
DataTable	this

Returns

Type	Description
IEnumerable<Object>

Examples

var dt = new DataTable();
dt.Columns.Add("col1", typeof(string));
dt.Columns.Add("col2", typeof(DateTime));
dt.Columns.Add("col3", typeof(decimal));
dt.Columns.Add("col4", typeof(string));
dt.Columns.Add("col5", typeof(string));
dt.Rows.Add("strVal", new DateTime(2019, 4, 1), 100.23m, DBNull.Value, null);
dt.Rows.Add("strVal2", new DateTime(2019, 4, 2), 122.23m, DBNull.Value, null);
var rs = dt.ToDynamicObjects().ToList();

// rs[0].col1 == "strVal"
// rs[0].col2 == new DateTime(2019, 4, 1)
// rs[1].col3 == 122.23m
// rs[1].col4 is null
// rs[1].col5 is null

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ToEntityList<T>(DataTable)

转换为实体列表

使用DataRow中的值，填充目标类型的 FieldInfo 与 PropertyInfo

匹配规则: FieldInfo.Name 或 PropertyInfo.Name 与 ColumnName 相同

Declaration

public static List<T> ToEntityList<T>(this DataTable this)
    where T : class, new()

Parameters

Type	Name	Description
DataTable	this

Returns

Type	Description
List<T>	返回 List<`T`>

Type Parameters

Name	Description
T	目标类型

Examples

var rs = dataTable.ToEntityList<TestClass1>();

Exceptions

Type	Condition
ArgumentNullException	`this`.DataRow 为空
InvalidCastException
FieldAccessException
TargetException
ArgumentException
MethodAccessException
TargetInvocationException
ArgumentNullException	`this`.RowsEnumerable(DataTable) 为空

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ToEntityList<T>(DataTable, Func<DataRow, T, T>)

转换为实体列表

Declaration

public static List<T> ToEntityList<T>(this DataTable this, Func<DataRow, T, T> converter)
    where T : class, new()

Parameters

Type	Name	Description
DataTable	this
Func<DataRow, T, T>	converter	参数 DataRow: 当前行参数 `T`: 目标新实例

Returns

Type	Description
List<T>	返回 List<`T`>

Type Parameters

Name	Description
T	目标类型

Examples

var rs = dt.ToEntityList<TestClass1>((row, newObj) =>
{
newObj.PublicField = row.Cell<string>("PublicField");
return newObj;
});

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Update<T>(DataTable, Func<DataRow, Boolean>, String, T)

更新

出现异常时，使用 DBNull.Value 进行填充

Declaration

public static void Update<T>(this DataTable this, Func<DataRow, bool> selector, string columnName, T value)

Parameters

Type	Name	Description
DataTable	this
Func<DataRow, Boolean>	selector	DataRow 选择器
String	columnName	列名
T	value

Type Parameters

Name	Description
T

Examples

dataTable.Update(row=> row["FRowId"].toString().Equals("rowId"), "FName", "this is name");
// it like SQL: UPDATE [table] SET FName = 'this is name' WHERE FRowId = 'rowId'

Exceptions

Type	Condition
ArgumentNullException	`columnName` is null
ArgumentNullException	`T` is null
ArgumentException	`columnName` not exist

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Update<T>(DataTable, Func<DataRow, Boolean>, String, Func<Int32, DataRow, T>)

更新

出现异常时，使用 DBNull.Value 进行填充

Declaration

public static void Update<T>(this DataTable this, Func<DataRow, bool> selector, string columnName, Func<int, DataRow, T> func)

Parameters

Type	Name	Description
DataTable	this
Func<DataRow, Boolean>	selector	DataRow 选择器
String	columnName	列名
Func<Int32, DataRow, T>	func	委托方法 int: index DataRow: 当前 DataRow

Type Parameters

Name	Description
T

Examples

_testTable1.Update(row=>true, "FName", (i, row) => $"{i}_{row["FRowId"]}");

Exceptions

Type	Condition
ArgumentNullException	`columnName` is null
ArgumentNullException	`T` is null
ArgumentException	`columnName` not exist

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Update<T>(DataTable, String, T)

更新

出现异常时，使用 DBNull.Value 进行填充

Declaration

public static void Update<T>(this DataTable this, string columnName, T value)

Parameters

Type	Name	Description
DataTable	this
String	columnName	列名
T	value

Type Parameters

Name	Description
T

Examples

_testTable1.Update("FName", "a");
// it like SQL: UPDATE [table] set FName = 'a'

Exceptions

Type	Condition
ArgumentNullException	`columnName` is null
ArgumentNullException	`T` is null
ArgumentException	`columnName` not exist