Question

我正在尝试将我的数据库绑定到一个组合框（“ProjectComboBox”），似乎无法让它工作。我试过在XAML中传递它，以及后端代码，但Combobox总是空白的。任何帮助将不胜感激。

SQL Server（本地）数据库：“Database1”

数据源：（DataSet1）;表：（ProjectTable）;

组合框名称：“ProjectComboBox”

这是我的XAML代码：

<Window x:Class="WpfApplication1.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:WpfApplication1"
    mc:Ignorable="d"
    Title="MainWindow" Height="500" Width="850">
<Grid>
    <ComboBox x:Name="ProjectComboBox"
              ItemsSource="{Binding Path=ProjectTable}"
              DisplayMemberPath="ProjectName" 
              SelectedValuePath="RFIDirectory" 
              HorizontalAlignment="Left" 
              VerticalAlignment="Top" 
              Width="297" Height="26" 
              SelectionChanged="comboBox_SelectionChanged">
    </ComboBox>

这是我的后端代码：

namespace WpfApplication1

public partial class MainWindow : Window
{
    public DataSet1 ProjectTable { get; set; }
    public MainWindow()
    {
        InitializeComponent();

    private void comboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        ProjectComboBox.Items.Clear();

        SqlConnection con = new SqlConnection("Data Source=(local);Initial Catalog=Database1;Integrated Security=True");

        try
        {
            con.Open();
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.ToString());
        }
        try
        {
            SqlDataAdapter ProjectTableTableAdapter = new SqlDataAdapter("SELECT * FROM PROJECTNAME", con);
            DataSet1 ds = new DataSet1();
            ProjectTableTableAdapter.Fill(ds, "t");

            ProjectComboBox.ItemsSource = ds.Tables["t"].DefaultView;
            ProjectComboBox.DisplayMemberPath = "ProjectName";
            ProjectComboBox.SelectedValuePath = "RFIDirectory";

        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.ToString());
        }

    }
}

}

Answer 1

您无法直接绑定到SQL Server表记录。但是，您可以绑定到表示表记录的对象列表。
正如@Paul Abbott所提到的，一旦表单加载，您必须首先初始化组合框项目。或者一个丑陋的方法是添加一个虚拟记录，一旦你选择它，将引发选择更改事件，然后你的代码将执行。
不要为连接open和sql数据适配器单独执行try-catch块。这是多余的。

在sql连接上使用using语句以正确关闭并在之后进行处置。

public MainWindow()
{
    InitializeComponent();
    UpdateItems(); // Maybe initialize here?
}

private void comboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    ProjectComboBox.Items.Clear(); // Remove this. AFAIK, the selected item will be cleared.
    UpdateItems();
}

private void UpdateItems()
{
    try
    {
        using(SqlConnection con = new SqlConnection("Data Source=(local);Initial Catalog=Database1;Integrated Security=True"))
        {
            con.Open();
            SqlDataAdapter ProjectTableTableAdapter = new SqlDataAdapter("SELECT * FROM PROJECTNAME", con);
            DataSet1 ds = new DataSet1();
            ProjectTableTableAdapter.Fill(ds, "t");

            ProjectComboBox.ItemsSource = ds.Tables["t"].DefaultView;
            ProjectComboBox.DisplayMemberPath = "ProjectName";
            ProjectComboBox.SelectedValuePath = "RFIDirectory";
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.ToString());
    } 
}

<ComboBox x:Name="ProjectComboBox"
      ItemsSource="{Binding Path=ProjectTable}" // Not sure of what the impact will be by adding this because you have already defined the item source on your code-behind. I'd prefer you remove this and use XAML binding when you're following a design pattern like MVVM or MVPVM.
      DisplayMemberPath="ProjectName" 
      SelectedValuePath="RFIDirectory" 
      HorizontalAlignment="Left" 
      VerticalAlignment="Top" 
      Width="297" Height="26" 
      SelectionChanged="comboBox_SelectionChanged">
</ComboBox>

c＃wpf将combobox绑定到SQL Server数据库

1 个答案: