ADO.NET对象的构造(7)_OleDbParameter(下)

新客网 XKER.COM 2004-05-17 来源： 收藏本文

n Overloads Public Overridable Function Add(ByVal value As Object) As Integer Implements IList.Add

n Overloads Public Function Add(ByVal parameterName As String,ByVal value As Object) As OleDbParameter

n Overloads Public Function Add(ByVal value As OleDbParameter) As OleDbParameter

n Overloads Public Function Add(ByVal parameterName As String,ByVal oleDbType As OleDbType) As OleDbParameter

n Overloads Public Function Add(ByVal parameterName As String,ByVal oleDbType As OleDbType,ByVal size As Integer) As OleDbParameter

n Overloads Public Function Add(ByVal parameterName As String,ByVal oleDbType As OleDbType,ByVal size As Integer,ByVal sourceColumn As String) As OleDbParameter




示例

Public Sub CreateOleDbParamColl(myConn As OleDbConnection)

Dim myCommand As OleDbCommand = New OleDbCommand("SELECT * FROM Customers WHERE CustomerID = ?", myConn)

Dim myParamCollection As OleDbParameterCollection = myCommand.Parameters



Dim myParm As Object = New OleDbParameter("CustomerID", OleDbType.VarChar)

Dim pIndex As Integer = myParamCollection.Add(myParm)



Dim myParm As OleDbParameter = myParamCollection.Add(New OleDbParameter("CustomerID", OleDbType.VarChar))



Dim myParm As OleDbParameter = myParamCollection.Add("CustomerID", “CustomerIDValue”);



Dim myParm As OleDbParameter = myParamCollection.Add("CustomerID", OleDbType.VarChar)



Dim myParm As OleDbParameter = myParamCollection.Add("CustomerID", OleDbType.VarChar, 5)



Dim myParm As OleDbParameter = myParamCollection.Add("CustomerID", OleDbType.VarChar, 5, "CustomerID")



End Sub



示例

Public Shared Function CreateCustomerAdapter(conn As OleDbConnection) As OleDbDataAdapter

Dim da As OleDbDataAdapter = New OleDbDataAdapter()

Dim cmd As OleDbCommand

Dim parm As OleDbParameter



' Create the SelectCommand.

cmd = New OleDbCommand("SELECT * FROM Customers WHERE Country = @Country AND City = @City", conn)

cmd.Parameters.Add("@Country", OleDbType.VarChar, 15)

cmd.Parameters.Add("@City", OleDbType.VarChar, 15)

da.SelectCommand = cmd



' Create the InsertCommand.

cmd = New OleDbCommand("INSERT INTO Customers (CustomerID, CompanyName) VALUES (@CustomerID, @CompanyName)", conn)

cmd.Parameters.Add("@CustomerID", OleDbType.Char, 5, "CustomerID")

cmd.Parameters.Add("@CompanyName", OleDbType.VarChar, 40, "CompanyName")

da.InsertCommand = cmd



' Create the DeleteCommand.

cmd = New OleDbCommand("DELETE FROM Customers WHERE CustomerID = @CustomerID", conn)

parm = cmd.Parameters.Add("@CustomerID", OleDbType.Char, 5, "CustomerID")

parm.SourceVersion = DataRowVersion.Original

da.DeleteCommand = cmd



' Create the UpdateCommand.

cmd = New OleDbCommand("UPDATE Customers SET CustomerID = @CustomerID, CompanyName = @CompanyName WHERE CustomerID = @oldCustomerID", conn)

cmd.Parameters.Add("@CustomerID", OleDbType.Char, 5, "CustomerID")

cmd.Parameters.Add("@CompanyName", OleDbType.VarChar, 40, "CompanyName")

parm = cmd.Parameters.Add("@oldCustomerID", OleDbType.Char, 5, "CustomerID")

parm.SourceVersion = DataRowVersion.Original

da.UpdateCommand = cmd



Return da

End Function



以下两行

parm = cmd.Parameters.Add("@CustomerID", OleDbType.Char, 5, "CustomerID")

parm.SourceVersion = DataRowVersion.Original

可以缩写为

cmd.Parameters.Add("@CustomerID", OleDbType.Char, 5, "CustomerID").SourceVersion = DataRowVersion.Original

类似地当添加参数后马上进行设置参数的值时,也可以进行类似以下缩写

myDataAdapter.SelectCommand.Parameters.Add("@CategoryName", OleDbType.VarChar, 80).Value = "toasters"

myDataAdapter.SelectCommand.Parameters.Add("@SerialNum", OleDbType.Integer).Value = 239

(信息整理来自MSDN)

• ·身份证函数 查看身份证地区信息
• ·VS2008 第一次安装心得及使用
• ·ASP.NET 2.0跨网页提交的三法
• ·编程实例 WebGroupBox(Aspx控件)
• ·asp.net mvc脚手架代码生成工具
• ·用独立的DLL来存储图片(资源文件)
• ·ASP.NET中多国语言的实现方法
• ·实例 .net生成静态页方法总结
• ·ASP.NET控件学习笔记之ViewState
• ·用递归在TreeView价节点
• ·经验总结 关于.NET 中的Event机制
• ·.NET应用程序开发标准化(z)
• ·在DataTable中查询应该注意的问题
• ·LINQ 中调用存储过程自动绑定列名
• ·如何用.NET技术在线生成网站LOGO
• ·对于访问IIS元数据库失败的解决