如何将参数传递给 SqlDataAdapter

Posted 2023-05-08

【中文标题】如何将参数传递给 SqlDataAdapter

【英文标题】：How to pass parameters to SqlDataAdapter

【发布时间】：2014-06-03 19:40:23

【问题描述】：

我有一个 Vb.net 程序，它查询数据库以获取一堆记录。我不太清楚如何传递参数。以下是我的代码：

Dim connectionString As String
    Dim sqlCnn As SqlConnection
    Dim sqlCmd As SqlCommand
    Dim sql As String

    Private Function GetCustomerData() As DataTable
        locationdb = "10.0.1.1"

        connectionString = ("Data Source=" & locationdb & ";Initial     Catalog=TestDB;Persist Security Info=True;User ID=user;Password=password")
        sql = ("SELECT lCustomerID,CustomerName,address FROM customers where @active = True...ETC")
        sqlCnn = New SqlConnection(connectionString)
        Dim CategoryAdapter As New SqlDataAdapter(sql, sqlCnn)
        Dim CustomerInfo As New DataSet()
        sqlCmd.Parameters.AddWithValue("@StartDate", frmMain.Startdate)
        sqlCmd.Parameters.AddWithValue("@EndDate", frmMain.Enddate)
        sqlCmd.Parameters.AddWithValue("@Department", "ALL")
        sqlCmd.Parameters.AddWithValue("@Active", "1")
        sqlCmd.Parameters.AddWithValue("@Visits", "ALL")
        CategoryAdapter.Fill(CustomerInfo, "Customers")
        Return CustomerInfo.Tables(0)
    End Function

我需要通过：

@stardate
@enddate
@Deparment
@Active
@Visits

我收到错误：

   NullReferenceException was unhandled.  Object reference not set to an instance of an    object.

在线：

  sqlCmd.Parameters.AddWithValue("@StartDate", frmMain.Startdate)

frmMain.Startdate 和 frmMain.Enddate 由 frmMain 上的日期时间选择器 datetimepicker1 and datetimepicker2 定义

【问题讨论】：

您是否完成或执行了 GOOGLE 对 SqlDataAdapter 和 Parameters.AddWithValue() 方法的搜索

这其实很简单，我会将我的 C# 方法转换为 VB，您可以将其用作模板/指南，下次尝试显示更多的努力

msdn.microsoft.com/en-us/library/yy6y35y8(v=vs.110).aspx

msdn.microsoft.com/en-us/library/… 太容易了

我将编辑我的帖子。我整个下午都在尝试，但我继续遇到错误。也许我应该张贴我得到的地方，而不是张贴我的“重新开始”点

【参考方案1】：

这里是一个例子，你可以使用什么以及如何传递参数 您必须在必要时进行更改

Public Shared Function GetCustomerInfo(stardate As DateTime, enddate As DateTime, Department As String, Active as String, Visits as Int33) As List(Of String)
    Dim cszList = New List(Of String)()
    Dim DSCityStateZipLookup As New DataSet()
    'load the List one time to be used thru out the intire application
    Dim ConnString = System.Configuration.ConfigurationManager.ConnectionStrings("CMSConnectionString").ConnectionString
    Using connStr As New SqlConnection(ConnString)
        Using cmd As New SqlCommand("your Stored Proc name goes here", connStr)
            cmd.Parameters.AddWithValue("@stardate", stardate)//make sure you assign a value to startdate
            cmd.Parameters.AddWithValue("@enddate", enddate)//make sure you assign a value to enddate
            cmd.Parameters.AddWithValue("@Deparment", Deparment)//make sure you assign a value to //Department
            cmd.Parameters.AddWithValue("@Active", Active)//make sure you assign a value to Active
            cmd.Parameters.AddWithValue("@Visits", Visits)//make sure you assign a value to Visits
            cmd.Connection.Open()
            New SqlDataAdapter(cmd).Fill(DSCityStateZipLookup)
            'If we get a record back from the above stored procedure call, that in itself means the information the user provided from
            'the UI is in the database. On the other hand, if we do not get a record back from the stored procedure call, we should
            'simply advise the user that the information they provided does not exist in the database, and to double check their spelling.
            If DSCityStateZipLookup.Tables.Count = 0 OrElse (DSCityStateZipLookup.Tables.Count > 0 AndAlso DSCityStateZipLookup.Tables(0).Rows.Count = 0) Then
                cszList.Add("Your Error Message goes here if any.")
            End If
        End Using
    End Using
    Return cszList
End Function

【讨论】：

我没有传入 SQL 注入代码 我创建了一个存储过程 研究代码示例并从 ConnString 向下执行代码并替换以及添加缺少的参数 @LarsTech 感谢您的编辑

是的，对于存储过程，将存储过程作为第一个参数传递给sqlCommand 这里：msdn.microsoft.com/en-us/library/… 或设置CommandText 属性。根据 CTOR msdn.microsoft.com/en-us/library/877h0y3a%28v=vs.110%29.aspx

prokchop 你在做什么你不能看发布的代码

'New SqlDataAdapter(cmd).Fill(DSCityStateZipLookup)' 是 vb.net 中的语法错误

应该是Dim DBA = New SqlDataAdapter(cmd)... 或Using。或者好吧......另外，sqlCommand 上的 Using 块是不必要的。打开连接也是多余的。数据适配器会这样做。