SqlParameterCollection.Contains 方法

参考

定义

命名空间:: System.Data.SqlClient

程序集:: System.Data.SqlClient.dll

程序集:: System.Data.dll

包:: System.Data.SqlClient v4.8.6

重要

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确定指定的对象是否在此 SqlParameterCollection 中。

重载

Contains(SqlParameter)	确定指定的 SqlParameter 是否在此 SqlParameterCollection 中。
Contains(Object)	确定指定的 Object 是否在此 SqlParameterCollection 中。
Contains(String)	确定指定的参数名是否在SqlParameterCollection。

Contains(SqlParameter)

确定指定的 SqlParameter 是否在此 SqlParameterCollection 中。

public:
 bool Contains(System::Data::SqlClient::SqlParameter ^ value);

public bool Contains (System.Data.SqlClient.SqlParameter value);

override this.Contains : System.Data.SqlClient.SqlParameter -> bool

Public Function Contains (value As SqlParameter) As Boolean

参数

value: SqlParameter

SqlParameter 值。

Boolean

如果 SqlParameterCollection 包含此值，则返回 true；否则，返回 false。

另请参阅

适用于

Contains(Object)

确定指定的 Object 是否在此 SqlParameterCollection 中。

public:
 override bool Contains(System::Object ^ value);

public:
 virtual bool Contains(System::Object ^ value);

public override bool Contains (object value);

public bool Contains (object value);

override this.Contains : obj -> bool

abstract member Contains : obj -> bool
override this.Contains : obj -> bool

Public Overrides Function Contains (value As Object) As Boolean

Public Function Contains (value As Object) As Boolean

参数

value: Object

Object 值。

Boolean

如果 SqlParameterCollection 包含此值，则返回 true；否则，返回 false。

实现

Contains(Object)

示例

下面的示例演示 IList 接口的实现以创建具有固定大小的简单列表。此代码是接口的更大示例的 IList 一部分。

class SimpleList : IList
{
    private object[] _contents = new object[8];
    private int _count;

    public SimpleList()
    {
        _count = 0;
    }

    // IList Members
    public int Add(object value)
    {
        if (_count < _contents.Length)
        {
            _contents[_count] = value;
            _count++;

            return (_count - 1);
        }

        return -1;
    }

    public void Clear()
    {
        _count = 0;
    }

    public bool Contains(object value)
    {
        for (int i = 0; i < Count; i++)
        {
            if (_contents[i] == value)
            {
                return true;
            }
        }
        return false;
    }

    public int IndexOf(object value)
    {
        for (int i = 0; i < Count; i++)
        {
            if (_contents[i] == value)
            {
                return i;
            }
        }
        return -1;
    }

    public void Insert(int index, object value)
    {
        if ((_count + 1 <= _contents.Length) && (index < Count) && (index >= 0))
        {
            _count++;

            for (int i = Count - 1; i > index; i--)
            {
                _contents[i] = _contents[i - 1];
            }
            _contents[index] = value;
        }
    }

    public bool IsFixedSize
    {
        get
        {
            return true;
        }
    }

    public bool IsReadOnly
    {
        get
        {
            return false;
        }
    }

    public void Remove(object value)
    {
        RemoveAt(IndexOf(value));
    }

    public void RemoveAt(int index)
    {
        if ((index >= 0) && (index < Count))
        {
            for (int i = index; i < Count - 1; i++)
            {
                _contents[i] = _contents[i + 1];
            }
            _count--;
        }
    }

    public object this[int index]
    {
        get
        {
            return _contents[index];
        }
        set
        {
            _contents[index] = value;
        }
    }

    // ICollection members.

    public void CopyTo(Array array, int index)
    {
        for (int i = 0; i < Count; i++)
        {
            array.SetValue(_contents[i], index++);
        }
    }

    public int Count
    {
        get
        {
            return _count;
        }
    }

    public bool IsSynchronized
    {
        get
        {
            return false;
        }
    }

    // Return the current instance since the underlying store is not
    // publicly available.
    public object SyncRoot
    {
        get
        {
            return this;
        }
    }

    // IEnumerable Members

    public IEnumerator GetEnumerator()
    {
        // Refer to the IEnumerator documentation for an example of
        // implementing an enumerator.
        throw new NotImplementedException("The method or operation is not implemented.");
    }

    public void PrintContents()
    {
        Console.WriteLine($"List has a capacity of {_contents.Length} and currently has {_count} elements.");
        Console.Write("List contents:");
        for (int i = 0; i < Count; i++)
        {
            Console.Write($" {_contents[i]}");
        }
        Console.WriteLine();
    }
}

Public Class SimpleList
    Implements IList

    Private _contents(7) As Object
    Private _count As Integer

    Public Sub New()

        _count = 0
    End Sub

    ' IList members.
    Public Function Add(ByVal value As Object) As Integer Implements IList.Add
        If _count < _contents.Length Then
            _contents(_count) = value
            _count += 1

            Return _count - 1
        End If

        Return -1
    End Function

    Public Sub Clear() Implements IList.Clear
        _count = 0
    End Sub

    Public Function Contains(ByVal value As Object) As Boolean Implements IList.Contains
        For i As Integer = 0 To Count - 1
            If _contents(i) = value Then Return True
        Next

        Return False
    End Function

    Public Function IndexOf(ByVal value As Object) As Integer Implements IList.IndexOf
        For i As Integer = 0 To Count - 1
            If _contents(i) = value Then Return i
        Next
        Return -1
    End Function

    Public Sub Insert(ByVal index As Integer, ByVal value As Object) Implements IList.Insert

        If _count + 1 <= _contents.Length AndAlso index < Count AndAlso index >= 0 Then
            _count += 1

            For i As Integer = Count - 1 To index Step -1
                _contents(i) = _contents(i - 1)
            Next
            _contents(index) = value
        End If
    End Sub

    Public ReadOnly Property IsFixedSize() As Boolean Implements IList.IsFixedSize
        Get
            Return True
        End Get
    End Property

    Public ReadOnly Property IsReadOnly() As Boolean Implements IList.IsReadOnly
        Get
            Return False
        End Get
    End Property

    Public Sub Remove(ByVal value As Object) Implements IList.Remove
        RemoveAt(IndexOf(value))
    End Sub

    Public Sub RemoveAt(ByVal index As Integer) Implements IList.RemoveAt

        if index >= 0 AndAlso index < Count Then
            for i As Integer = index To Count - 2
                _contents(i) = _contents(i + 1)
            Next
            _count -= 1
        End If
    End Sub

    Public Property Item(ByVal index As Integer) As Object Implements IList.Item
        Get
            Return _contents(index)
        End Get

        Set(ByVal value As Object)
            _contents(index) = value
        End Set
    End Property

    ' ICollection members.
    Public Sub CopyTo(ByVal array As Array, ByVal index As Integer) Implements ICollection.CopyTo
        For i As Integer = 0 To Count - 1
            array.SetValue(_contents(i), index)
            index += 1
        Next
    End Sub

    Public ReadOnly Property Count() As Integer Implements ICollection.Count
        Get
            Return _count
        End Get
    End Property

    Public ReadOnly Property IsSynchronized() As Boolean Implements ICollection.IsSynchronized
        Get
            Return False
        End Get
    End Property

    ' Return the current instance since the underlying store is not
    ' publicly available.
    Public ReadOnly Property SyncRoot() As Object Implements ICollection.SyncRoot
        Get
            Return Me
        End Get
    End Property

    ' IEnumerable members.
    Public Function GetEnumerator() As IEnumerator Implements IEnumerable.GetEnumerator

        ' Refer to the IEnumerator documentation for an example of
        ' implementing an enumerator.
        Throw New NotImplementedException("The method or operation is not implemented.")
    End Function

    Public Sub PrintContents()
        Console.WriteLine($"List has a capacity of {_contents.Length} and currently has {_count} elements.")
        Console.Write("List contents:")

        For i As Integer = 0 To Count - 1
            Console.Write($" {_contents(i)}")
        Next

        Console.WriteLine()
    End Sub
End Class

注解

此成员是显式接口成员的实现。它只能在 SqlParameterCollection 实例被强制转换为 IList 接口时使用。

从 .NET Framework 2.0 开始，此方法使用集合的对象 Equals 和 CompareTo 方法item来确定项是否存在。在早期版本的.NET Framework中，此确定是通过对集合中的对象使用 Equals 参数的 item 和 CompareTo 方法进行的。

另请参阅

适用于

Contains(String)

确定指定的参数名是否在SqlParameterCollection。

public:
 override bool Contains(System::String ^ value);

public:
 virtual bool Contains(System::String ^ value);

public override bool Contains (string value);

public bool Contains (string value);

override this.Contains : string -> bool

abstract member Contains : string -> bool
override this.Contains : string -> bool

Public Overrides Function Contains (value As String) As Boolean

Public Function Contains (value As String) As Boolean

参数

value: String

String 值。

Boolean

如果 SqlParameterCollection 包含此值，则返回 true；否则，返回 false。

实现

Contains(String)

另请参阅

适用于

通过

SqlParameterCollection.Contains 方法

定义

重载

Contains(SqlParameter)

参数

返回

另请参阅

适用于

Contains(Object)

参数

返回

实现

示例

注解

另请参阅

适用于

Contains(String)

参数

返回

实现

另请参阅

适用于

其他资源