DataTypeInfos.Contains(Object) 方法
定义
重要
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返回一个布尔值，该值指示是否可以使用索引访问集合中的项，而不引发异常。
public:
bool Contains(System::Object ^ index);public bool Contains (object index);member this.Contains : obj -> boolPublic Function Contains (index As Object) As Boolean参数
- index
- Object
要在集合中找到的项的索引。
返回
一个布尔值，指示是否可以通过索引访问集合。 true 值指示可以使用语法 DataTypeInfos[index] 访问集合。 false 值指示索引不能用于从 DataTypeInfos 集合中检索项。
示例
以下示例使用该方法 Contains 查看集合中的项数。
using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.SqlServer.Dts.Runtime;
namespace DBProvInfos_GetEnum_Contains
{
class Program
{
static void Main(string[] args)
{
//Create the DataTypeInfos collection.
DataTypeInfos dataInfos = new Application().DataTypeInfos;
//Create the enumerator.
DataTypeInfoEnumerator myEnumerator = dataInfos.GetEnumerator();
Console.WriteLine("The collection contains the following values:");
int i = 0;
DataTypeInfo dtiObject;
while ((myEnumerator.MoveNext()) && (myEnumerator.Current != null))
{
dtiObject = (DataTypeInfo)myEnumerator.Current;
Console.WriteLine("[{0}] {1} {2}", i++, dtiObject.TypeName, dtiObject.TypeEnumName);
}
// Reset puts the index pointer before the beginning.
// Do not retrieve from the collection until MoveNext is called.
myEnumerator.Reset();
myEnumerator.MoveNext();
// Now that the enumerator has been reset, use Contains.
//Boolean contains30 = dataInfos.Contains(30);
Console.WriteLine("contains at least 30 data types? {0}", dataInfos.Contains(30));
Console.WriteLine("contains at least 20 data types? {0}", dataInfos.Contains(20));
// Now that the enumerator has been reset, and moved to the
// first item in the collection, show the first item.
//dtiObject = (DataTypeInfo)myEnumerator.Current;
//Console.WriteLine("The first item in the enumerator after Reset:");
//Console.WriteLine("{0}, {1}", dtiObject.TypeName, dtiObject.TypeEnumName);
Console.WriteLine();
}
}
}
Imports System
Imports System.Collections.Generic
Imports System.Text
Imports Microsoft.SqlServer.Dts.Runtime
Namespace DBProvInfos_GetEnum_Contains
Class Program
Shared Sub Main(ByVal args() As String)
'Create the DataTypeInfos collection.
Dim dataInfos As DataTypeInfos = New Application().DataTypeInfos
'Create the enumerator.
Dim myEnumerator As DataTypeInfoEnumerator = dataInfos.GetEnumerator()
Console.WriteLine("The collection contains the following values:")
Dim i As Integer = 0
Dim dtiObject As DataTypeInfo
While (myEnumerator.MoveNext()) &&(myEnumerator.Current <> Nothing)
dtiObject = CType(myEnumerator.Current, DataTypeInfo)
Console.WriteLine("[{0}] {1} {2}",i = Console.WriteLine("[{0}] {1} {2}",i + 1
End While
' Reset puts the index pointer before the beginning.
' Do not retrieve from the collection until MoveNext is called.
myEnumerator.Reset()
myEnumerator.MoveNext()
' Now that the enumerator has been reset, use Contains.
'Boolean contains30 = dataInfos.Contains(30);
Console.WriteLine("contains at least 30 data types? {0}", dataInfos.Contains(30))
Console.WriteLine("contains at least 20 data types? {0}", dataInfos.Contains(20))
' Now that the enumerator has been reset, and moved to the
' first item in the collection, show the first item.
'dtiObject = (DataTypeInfo)myEnumerator.Current;
'Console.WriteLine("The first item in the enumerator after Reset:");
'Console.WriteLine("{0}, {1}", dtiObject.TypeName, dtiObject.TypeEnumName);
Console.WriteLine()
End Sub
End Class
End Namespace
示例输出：
该集合包含以下值：
[0] 浮点DT_R4
[1] 双精度浮点DT_R8
[2] 货币DT_CY
[3] 日期DT_DATE
[4] 布尔DT_BOOL
[5] 十进制DT_DECIMAL
[6] 单字节带符号整数DT_I1
[7] 单字节无符号整数DT_UI1
[8] 双字节带符号整数DT_I2
[9] 双字节无符号整数DT_UI2
[10] 四字节有符号整数DT_I4
[11] 四字节无符号整数DT_UI4
[12] 八字节带符号整数DT_I8
[13] 八字节无符号整数DT_UI8
[14] 文件时间戳DT_FILETIME
[15] 唯一标识符DT_GUID
[16] 字节流DT_BYTES
[17] 字符串DT_STR
[18] Unicode 字符串DT_WSTR
[19] 数值DT_NUMERIC
[20] 数据库日期DT_DBDATE
[21] 数据库时间DT_DBTIME
[22] 数据库时间戳DT_DBTIMESTAMP
[23] 图像DT_IMAGE
[24] 文本流DT_TEXT
[25] Unicode 文本流DT_NTEXT
包含至少 30 种数据类型？ 错误
包含至少 20 种数据类型？ True