SqlParameterCollection.Contains 方法

定义

命名空间:

System.Data.SqlClient

程序集:

System.Data.dll

确定指定的对象是否在此中 SqlParameterCollection。

重载

名称	说明
Contains(SqlParameter)	确定指定的 SqlParameter 值是否在此中 SqlParameterCollection。
Contains(Object)	确定指定的 Object 值是否在此中 SqlParameterCollection。
Contains(String)	确定指定的参数名称是否在此中 SqlParameterCollection。

Contains(SqlParameter)

确定指定的 SqlParameter 值是否在此中 SqlParameterCollection。

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

值 SqlParameter 。

返回

Boolean

true 如果包含该值，则为 SqlParameterCollection ;否则为 false。

另请参阅

• 命令和参数 （ADO.NET）
• DataAdapter 参数 （ADO.NET）
• 使用适用于 SQL Server 的 .NET Framework 数据提供程序
• ADO.NET 概述

Contains(Object)

确定指定的 Object 值是否在此中 SqlParameterCollection。

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

public override bool Contains(object value);

override this.Contains : obj -> bool

Public Overrides Function Contains (value As Object) As Boolean

参数

value

Object

值 Object 。

返回

Boolean

true 如果包含该值，则为 SqlParameterCollection ;否则为 false。

示例

以下示例演示了接口的 IList 实现，以创建简单的固定大小列表。 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实现。 仅当实例强制转换为SqlParameterCollection接口时IList，才能使用它。

此方法使用集合的对象 Equals 和 CompareTo 方法 item 来确定是否存在 item 。

另请参阅

• 命令和参数 （ADO.NET）
• DataAdapter 参数 （ADO.NET）
• 使用适用于 SQL Server 的 .NET Framework 数据提供程序
• ADO.NET 概述

Contains(String)

确定指定的参数名称是否在此中 SqlParameterCollection。

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

public override bool Contains(string value);

override this.Contains : string -> bool

Public Overrides Function Contains (value As String) As Boolean

参数

value

String

值 String 。

返回

Boolean

true 如果包含该值，则为 SqlParameterCollection ;否则为 false。

另请参阅

• 命令和参数 （ADO.NET）
• DataAdapter 参数 （ADO.NET）
• 使用适用于 SQL Server 的 .NET Framework 数据提供程序
• ADO.NET 概述