用选定的值填充列表框 [英] Populate listbox with selected values

问题描述

我有一个用于Web应用程序的表单，该表单使用列表框控件选择类别.我没有问题，可以使用表中的数据填充列表框中的值并将其提取以保存.问题是当我去编辑时，找不到找到将相关记录标记为已选择的方法.

下面的第一个子项是填充表单中列表框的子项.第二个子项尝试从表中加载值，该表将主表中的记录与类别表中的记录相关联.

第二个子选项仅将阅读器中的最后一条记录标记为选中.我已经广泛搜索了应该是一个简单任务的解决方案，却一无所获.我可以用内联代码蒙住眼睛.这很令人沮丧.

I have a form for a web application that selects categories using a listbox control. I have no problem populating the values in the listbox with data from a table and extracting that to save. The problem is when I go to edit, I cannot find a way to mark the associated records as selected.

The first sub below is the sub that populates the listbox in the form. The second sub attempts to load values from a table that associates records from a primary table to records in the categories table.

The second sub only marks the last record in the reader as selected. I have searched extensively for a solution to what should be a simple task and have found nothing. I could do this blindfolded with inline code; this is frustrating.

Protected Sub LoadCat()
    Dim myCommand As New SqlCommand
    Dim myReader As SqlDataReader = Nothing
    Dim strConnection As String
    strConnection = ConfigurationManager.AppSettings("ConnectionString")

    Dim sPath = System.Web.HttpContext.Current.Request.Url.AbsolutePath
    Dim oInfo = New System.IO.FileInfo(sPath)
    Dim sRet = oInfo.Name

    Try
        myConnection = New SqlConnection(strConnection)
        myConnection.Open()
        'opening the connection
        With myCommand
            .CommandType = CommandType.StoredProcedure
            .CommandText = "MCC_LoadRecCat"
            .Connection = myConnection
            myReader = .ExecuteReader()
        End With
    Catch ex As Exception
        Dim EmailClass As New EmailClass
        EmailClass.EmailError(ex.Message.ToString, sRet, Session("ErrorEmail"), Session("EmailUser"), Session("EmailPassword"), Session("MailServer"))
        Response.Redirect("Error.aspx")
        Exit Sub
    End Try

    reccatID.DataSource = myReader
    reccatID.DataTextField = "reccatName"
    reccatID.DataValueField = "reccatID"
    reccatID.DataBind()

    myReader.Close()
    myCommand.Dispose()
    myConnection.Close()

End Sub

Protected Sub PopulateCat()
    Dim myCommand As New SqlCommand
    Dim myReader As SqlDataReader = Nothing
    Dim strConnection As String
    strConnection = ConfigurationManager.AppSettings("ConnectionString")

    Dim sPath = System.Web.HttpContext.Current.Request.Url.AbsolutePath
    Dim oInfo = New System.IO.FileInfo(sPath)
    Dim sRet = oInfo.Name

    Dim MyID = Request("ID")
    ViewState("recipeID") = Request("ID")

    Try
        myConnection = New SqlConnection(strConnection)
        myConnection.Open()
        'opening the connection
        With myCommand
            .CommandType = CommandType.StoredProcedure
            .CommandText = "MCC_GetRecipeCat2"
            .Parameters.Add("@recipeID", SqlDbType.Int).Value = MyID
            .Connection = myConnection
            myReader = .ExecuteReader()
        End With
    Catch
    End Try

    While myReader.Read
        reccatID.SelectedValue = myReader("catID")
    End While


    myReader.Close()
    myCommand.Dispose()
    myConnection.Close()
End Sub

推荐答案

您要一遍又一遍地设置选定的值.因此，每次都取消选择最后一个.我相信这里有一个SelectedValues属性，您可以添加一个集合.如果没有，则不能选择多个项目，

You''re setting the selectedvalue over and over. Thus, each time, you unselect the last one selected. I believe there''s a SelectedValues property, a collection you can add to. If there''s not, then you can''t select more than one item,

这篇关于用选定的值填充列表框的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！