Winter*** [ ^ ]写道：

在我问如何从填充了数据库的列表框中删除项目之前



是否可以从填充了数据库的列表框中删除项目？

直到 ListBox 控件未与数据源绑定，您可以轻松地从该控件中删除项目。您的 ListBox 对象未与数据源绑定，因此...请参阅：

ListBox.ObjectCollection.Remove方法（对象）（System.Windows.Forms） [ ^ ]

如何：在Windows窗体ComboBox，ListBox或CheckedListBox控件中添加和删除项目Microsoft Docs [ ^ ]

另一方面，您必须更新数据源而不是删除 ListBox 项目。请参阅：

如何：使用BindingSource反映Windows窗体控件中的数据源更新Microsoft Docs [ ^ ]

更新和重新绑定数据源参考 [ ^ ]

如何：更新包含来自主机控件的数据的数据源 [ ^ ]



祝你好运！

您可以使用 DataTable 之类的这个：

使用（SqlConnection conn = new SqlConnection（CONN_STR））
 using（SqlDataAdapter da = new sqlDataAdapter（roboticSiteNames，conn））{
 DataSet ds = new DataSet（）; 
 da.Fill（ds）; 
 DataTable dt = ds.Tables [0]; 

 // 1.设置DisplayMember和ValueMember 
 lbSiteCode.DisplayMember = dt.Columns [0] .ColumnName; 
 lbSiteCode.ValueMember = dt.Columns [1] .ColumnName; 
 // 2.设置DataSource 
 lbSiteCode.DataSource = dt; 
} 

这是答案： Datatable to listbox [ ^ ]



然后你可以删除DataTable中的行，参见如何：删除DataTable中的行 [ ^ ]



这也可以在 DataSet 中完成，例如

 NorthwindDataSet1.Customers.Rows（0）.Delete（）

当你正在使用 DataView 时，你可以使用 .RowFilter 像这样：

 dv.RowFilter =FirstName<'Peter'; 

请参阅： DataView.RowFilter Property（Sys tem.Data） [ ^ ]

这是一个很好的概述： DataView RowFilter语法[C＃] [ ^ 一>

Before i ask "How to remove an item from a listbox populated with a database"

Is it possible to remove an item from a listbox populated with a database?

What I have tried:

if it is possible, my code is not working:

Dim str As String
            Dim drv As DataRowView = CType(ListBox1.SelectedItem, DataRowView)
            str = CStr(drv.Row.Item("PName"))
            ListBox1.Items.Remove(ListBox1.SelectedItem(str))

This is how i populate my listbox:

'Populate the ListBox with personnelName from personnel '
       Try
           connection = New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\Nikko Jaze Fabellon\Documents\ASRASIM.accdb")
           connection.Open()
           ds = New DataSet
           tables = ds.Tables
           dataAdapter = New OleDbDataAdapter("SELECT [FirstName],[LastName] from [Personnel] where [Status] = 'Activated' ", connection)
           dataAdapter.Fill(ds, "Personnel")
           Dim view1 As New DataView(tables(0))
           With personnelList
               .DataSource = ds.Tables("Personnel")
               .DisplayMember = "FirstName"
               .ValueMember = "LastName"
               .SelectedIndex = 0
           End With

           connection.Close()

       Catch ex As Exception
           MessageBox.Show(ex.Message)
       End Try

or if it is not possible, i need advice to think of another way.

Winter***[^] wrote:

Before i ask "How to remove an item from a listbox populated with a database"

Is it possible to remove an item from a listbox populated with a database?

Untill a ListBox control is not bind with a datasource, you can easily remove item from that control. Your ListBox object is not bind with data source, so... See:
ListBox.ObjectCollection.Remove Method (Object) (System.Windows.Forms)[^]
How to: Add and Remove Items from a Windows Forms ComboBox, ListBox, or CheckedListBox Control | Microsoft Docs[^]
In the other way, you have to update datasource instead of removing ListBox item. See:
How to: Reflect Data Source Updates in a Windows Forms Control with the BindingSource | Microsoft Docs[^]
Updating and Rebinding Data Source References[^]
How to: Update a Data Source with Data from a Host Control[^]

Good luck!

You could use a DataTable like this:

using (SqlConnection conn = new SqlConnection(CONN_STR))
using (SqlDataAdapter da = new sqlDataAdapter("roboticSiteNames", conn)) {
DataSet ds = new DataSet();
da.Fill(ds);
DataTable dt = ds.Tables[0];

// 1. set DisplayMember and ValueMember
lbSiteCode.DisplayMember = dt.Columns[0].ColumnName;
lbSiteCode.ValueMember = dt.Columns[1].ColumnName;
// 2. set DataSource
lbSiteCode.DataSource = dt;
}

This is from an answer here: Datatable to listbox[^]

Then you can delete rows in the DataTable, see How to: Delete Rows in a DataTable[^]

This can also be done in a DataSet, e.g.

NorthwindDataSet1.Customers.Rows(0).Delete()

As you are using a DataView now, you can use .RowFilter like this:

dv.RowFilter = "FirstName < 'Peter'";

See: DataView.RowFilter Property (System.Data)[^]
Here is a nice overview: DataView RowFilter Syntax [C#][^]