SqlParameterCollection.IndexOf 方法
定义
获取指定的 SqlParameter 在集合中的位置。Gets the location of the specified SqlParameter within the collection.
重载
| IndexOf(SqlParameter) |
获取指定的 SqlParameter 在集合中的位置。Gets the location of the specified SqlParameter within the collection. |
| IndexOf(Object) |
获取指定的 Object 在集合中的位置。Gets the location of the specified Object within the collection. |
| IndexOf(String) |
获取具有指定名称的指定 SqlParameter 的位置。Gets the location of the specified SqlParameter with the specified name. |
IndexOf(SqlParameter)
获取指定的 SqlParameter 在集合中的位置。Gets the location of the specified SqlParameter within the collection.
public:
int IndexOf(System::Data::SqlClient::SqlParameter ^ value);
public int IndexOf (System.Data.SqlClient.SqlParameter value);
override this.IndexOf : System.Data.SqlClient.SqlParameter -> int
Public Function IndexOf (value As SqlParameter) As Integer
参数
- value
- SqlParameter
要查找的 SqlParameter。The SqlParameter to find.
返回
指定的 SqlParameter(它是 SqlParameter)在集合中从零开始的位置。The zero-based location of the specified SqlParameter that is a SqlParameter within the collection. 如果 SqlParameterCollection 中不存在该对象,则返回 -1。Returns -1 when the object does not exist in the SqlParameterCollection.
适用于
IndexOf(Object)
public:
override int IndexOf(System::Object ^ value);
public:
virtual int IndexOf(System::Object ^ value);
public override int IndexOf (object value);
public int IndexOf (object value);
override this.IndexOf : obj -> int
abstract member IndexOf : obj -> int
override this.IndexOf : obj -> int
Public Overrides Function IndexOf (value As Object) As Integer
Public Function IndexOf (value As Object) As Integer
参数
返回
指定的 Object(它是 SqlParameter)在集合中从零开始的位置。The zero-based location of the specified Object that is a SqlParameter within the collection. 如果 SqlParameterCollection 中不存在该对象,则返回 -1。Returns -1 when the object does not exist in the SqlParameterCollection.
实现
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。The following example demonstrates the implementation of the IList interface to create a simple, fixed-size list. 此代码是接口的更大示例的一部分 IList 。This code is part of a larger example for the IList interface.
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。This member is an explicit interface member implementation. 它只能在 SqlParameterCollection 实例被强制转换为 IList 接口时使用。It can be used only when the SqlParameterCollection instance is cast to an IList interface.
从 .NET Framework 2.0 开始,此方法使用集合的对象的 Equals 和 CompareTo 方法 item 来确定项是否存在。Starting with the .NET Framework 2.0, this method uses the collection's objects' Equals and CompareTo methods on item to determine whether item exists. 在 .NET Framework 的早期版本中,此决定是通过对 Equals CompareTo item 集合中的对象使用参数的和方法进行的。In the earlier versions of the .NET Framework, this determination was made by using the Equals and CompareTo methods of the item parameter on the objects in the collection.
适用于
IndexOf(String)
获取具有指定名称的指定 SqlParameter 的位置。Gets the location of the specified SqlParameter with the specified name.
public:
override int IndexOf(System::String ^ parameterName);
public:
virtual int IndexOf(System::String ^ parameterName);
public override int IndexOf (string parameterName);
public int IndexOf (string parameterName);
override this.IndexOf : string -> int
abstract member IndexOf : string -> int
override this.IndexOf : string -> int
Public Overrides Function IndexOf (parameterName As String) As Integer
Public Function IndexOf (parameterName As String) As Integer
参数
- parameterName
- String
要查找的 SqlParameter 的名称(区分大小写)。The case-sensitive name of the SqlParameter to find.
返回
具有指定名称(区分大小写)的指定 SqlParameter 的位置(从零开始)。The zero-based location of the specified SqlParameter with the specified case-sensitive name. 如果 SqlParameterCollection 中不存在该对象,则返回 -1。Returns -1 when the object does not exist in the SqlParameterCollection.