国产探花免费观看_亚洲丰满少妇自慰呻吟_97日韩有码在线_资源在线日韩欧美_一区二区精品毛片,辰东完美世界有声小说,欢乐颂第一季,yy玄幻小说排行榜完本

首頁 > 編程 > .NET > 正文

DataView.RowFilter的使用(包括in,like等SQL中的操作符)

2020-01-18 00:40:43
字體:
來源:轉載
供稿:網友

DataView RowFilter Syntax [C#]
This example describes syntax of DataView.RowFil ter expression. It shows how to correctly build expression string (without „SQL injection“) using methods to escape values.

Column names
If a column name contains any of these special characters ~ ( ) # / / = > < + - * % & | ^ ' " [ ], you must enclose the column name within square brackets [ ]. If a column name contains right bracket ] or backslash /, escape it with backslash (/] or //).

[C#]

dataView.RowFilter = "id = 10"; // no special character in column name "id" dataView.RowFilter = "$id = 10"; // no special character in column name "$id" dataView.RowFilter = "[#id] = 10"; // special character "#" in column name "#id" dataView.RowFilter = "[[id/]] = 10"; // special characters in column name "[id]"
Literals
String values are enclosed within single quotes ' '. If the string contains single quote ', the quote must be doubled.

[C#]

dataView.RowFilter = "Name = 'John'" // string value dataView.RowFilter = "Name = 'John ''A'''" // string with single quotes "John 'A'" dataView.RowFilter = String.Format("Name = '{0}'", "John 'A'".Replace("'", "''"));
Number values are not enclosed within any characters. The values should be the same as is the result of int.ToString() or float.ToString() method for invariant or English culture.

[C#]

dataView.RowFilter = "Year = 2008" // integer value dataView.RowFilter = "Price = 1199.9" // float value dataView.RowFilter = String.Format(CultureInfo.InvariantCulture.NumberFormat, "Price = {0}", 1199.9f);
Date values are enclosed within sharp characters # #. The date format is the same as is the result of DateTime.ToString() method for invariant or English culture.

[C#]

dataView.RowFilter = "Date = #12/31/2008#" // date value (time is 00:00:00) dataView.RowFilter = "Date = #2008-12-31#" // also this format is supported dataView.RowFilter = "Date = #12/31/2008 16:44:58#" // date and time value dataView.RowFilter = String.Format(CultureInfo.InvariantCulture.DateTimeFormat, "Date = #{0}#", new DateTime(2008, 12, 31, 16, 44, 58));
Alternatively you can enclose all values within single quotes ' '. It means you can use string values for numbers or date time values. In this case the current culture is used to convert the string to the specific value.

[C#]

dataView.RowFilter = "Date = '12/31/2008 16:44:58'" // if current culture is English dataView.RowFilter = "Date = '31.12.2008 16:44:58'" // if current culture is German dataView.RowFilter = "Price = '1199.90'" // if current culture is English dataView.RowFilter = "Price = '1199,90'" // if current culture is German
Comparison operators
Equal, not equal, less, greater operators are used to include only values that suit to a comparison expression. You can use these operators = <> < <= > >=.

Note: String comparison is culture-sensitive, it uses CultureInfo from DataTable.Locale property of related table (dataView.Table.Locale). If the property is not explicitly set, its default value is DataSet.Locale (and its default value is current system culture Thread.Curren tThread.Curren tCulture).

[C#]

dataView.RowFilter = "Num = 10" // number is equal to 10 dataView.RowFilter = "Date < #1/1/2008#" // date is less than 1/1/2008 dataView.RowFilter = "Name <> 'John'" // string is not equal to 'John' dataView.RowFilter = "Name >= 'Jo'" // string comparison
Operator IN is used to include only values from the list. You can use the operator for all data types, such as numbers or strings.

[C#]

dataView.RowFilter = "Id IN (1, 2, 3)" // integer values dataView.RowFilter = "Price IN (1.0, 9.9, 11.5)" // float values dataView.RowFilter = "Name IN ('John', 'Jim', 'Tom')" // string values dataView.RowFilter = "Date IN (#12/31/2008#, #1/1/2009#)" // date time values dataView.RowFilter = "Id NOT IN (1, 2, 3)" // values not from the list
Operator LIKE is used to include only values that match a pattern with wildcards. Wildcard character is * or %, it can be at the beginning of a pattern '*value', at the end 'value*', or at both '*value*'. Wildcard in the middle of a patern 'va*lue' is not allowed.

[C#]

dataView.RowFilter = "Name LIKE 'j*'" // values that start with 'j' dataView.RowFilter = "Name LIKE '%jo%'" // values that contain 'jo' dataView.RowFilter = "Name NOT LIKE 'j*'" // values that don't start with 'j'
If a pattern in a LIKE clause contains any of these special characters * %

發表評論 共有條評論
用戶名: 密碼:
驗證碼: 匿名發表
主站蜘蛛池模板: 江永县| 温宿县| 盘锦市| 巨野县| 双柏县| 峨眉山市| 丹巴县| 沈阳市| 堆龙德庆县| 那坡县| 荥阳市| 年辖:市辖区| 巧家县| 枣庄市| 西乌珠穆沁旗| 郑州市| 汉中市| 远安县| 惠州市| 仙居县| 区。| 龙海市| 广平县| 孝感市| 灵寿县| 湘潭县| 马龙县| 元氏县| 旬阳县| 宜宾市| 塔城市| 志丹县| 白河县| 望城县| 新密市| 屯昌县| 和龙市| 新邵县| 玉山县| 广安市| 龙川县|