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两个数据表之间的数据关系-无法将数据绑定到列表框(C#.NET 3.5)

datarelation listbox data-binding visual-studio-2008 c#

Konrad Morawski · 技术社区 · 16 年前

C#(.NET 3.5)

我的表单包含文本框、复选框等来表示员工的详细信息,但我也希望有一个列表框,列出当前所选员工的所有假期。

        var command = new SQLiteCommand("SELECT * FROM employees; SELECT * FROM holidays");
        var connection=new SQLiteConnection(@"data source=C:\employees.db");
        command.Connection = connection;
        SQLiteDataAdapter adapter = new SQLiteDataAdapter(command);
        DataSet d = new DataSet();
        adapter.Fill(d);                        

        DataTable employees = d.Tables[0];

        // [...]
        // here I'm databinding my textboxes etc. to various columns 
        // of the employees data table - this works fine, navigation works well etc.
        // [...]

        DataTable holidays = d.Tables[1];            

        DataRelation relation;
        DataColumn master = employees.Columns[0];
        DataColumn slave = holidays.Columns[0];
        relation = new DataRelation("relation", master, slave);
        d.Relations.Add(relation);

        var dsView = holidays.DefaultView;
        listBox1.DisplayMember = "holidays.relation.start"; // <= it wouldn't look good like that of course, but I just want to get the thing to work for now
        listBox1.DataSource = dsView;

但我得到的只是一个列表框,里面装满了一堆“System.Data.DataRow” 在这个实现中,我试图遵循我在Akadia上找到的教程。。。我哪里出错了?谢谢

1 回复 | 直到 16 年前

Martin Booth 16 年前

首先,您已经命名了变量employees和holidays,但这确实意味着数据集中的表名称已经更改;它们仍然被设置为默认名称,在您的示例中是table和table1(它们通常是桌子,桌子1。。。表1) 这意味着您的显示成员属性应如下所示:

listBox1.DisplayMember = "table.relation.start";

listBox1.DataSource = d;

有了这两个变化,你会发现它是有效的;this.BindingContext应该有助于导航父记录,因为您会注意到此时只显示1组子(假日)结果。

完成修改后的代码,如下所示:

    var command = new SQLiteCommand("SELECT * FROM employees; SELECT * FROM holidays");
    var connection=new SQLiteConnection(@"data source=C:\employees.db");
    command.Connection = connection;
    SQLiteDataAdapter adapter = new SQLiteDataAdapter(command);
    DataSet d = new DataSet();
    adapter.Fill(d);                        

    DataTable employees = d.Tables[0];

    // [...]
    // here I'm databinding my textboxes etc. to various columns 
    // of the employees data table - this works fine, navigation works well etc.
    // [...]

    DataTable holidays = d.Tables[1];

    DataRelation relation;
    DataColumn master = employees.Columns["id"];
    DataColumn slave = holidays.Columns["employeeid"];
    relation = new DataRelation("relation", master, slave);
    d.Relations.Add(relation);


    listBox1.DisplayMember = "table.relation.start"; // <= it wouldn't look good like that of course, but I just want to get the thing to work for now
    listBox1.DataSource = d;