我正在尝试为我的课程制作拍卖申请。
namespace Auction
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
GetData("SELECT * FROM Produs");
btnLogout.Visibility = System.Windows.Visibility.Hidden;
btnAdd.Visibility = System.Windows.Visibility.Hidden;
btnBid.Visibility = System.Windows.Visibility.Hidden;
tb.Visibility = System.Windows.Visibility.Hidden;
}
private void GetData(string SelectCommand)
{
SqlConnection conn = new SqlConnection(@"Data Source=ISAAC;Initial Catalog=licitatie;Integrated Security=True");
conn.Open();
SqlCommand cmd = new SqlCommand(SelectCommand);
cmd.Connection = conn;
SqlDataAdapter sda = new SqlDataAdapter(cmd);
DataTable dt = new DataTable("prod");
sda.Fill(dt);
myGrid.DataContext = dt;
}
private void btnLogin_Click(object sender, RoutedEventArgs e)
{
Login login = new Login();
login.Show();
Close();
}
private void Button_Click(object sender, RoutedEventArgs e)
{
Countdown(30, TimeSpan.FromSeconds(1), cur => tb.Text = cur.ToString());
}
void Countdown(int count, TimeSpan interval, Action<int> ts)
{
var dt = new System.Windows.Threading.DispatcherTimer();
dt.Interval = interval;
dt.Tick += (_, a) =>
{
if (count-- == 0)
{
MessageBox.Show("You have won this product!");
dt.Stop();
}
else
ts(count);
};
ts(count);
dt.Start();
}
private void btnLogout_Click(object sender, RoutedEventArgs e)
{
MainWindow main = new MainWindow();
main.Show();
Close();
MessageBox.Show("You are not logged. Please log in to bid", "Failed",
MessageBoxButton.OK, MessageBoxImage.Information);
}
private void btnAdd_Click(object sender, RoutedEventArgs e)
{
Register reg = new Register();
reg.Show();
Close();
}
private void DataGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
var grid = sender as DataGrid;
var selected = grid.SelectedItem;
if (selected == grid.SelectedItem)
{
btnBid.Visibility = System.Windows.Visibility.Visible;
}
}
private void UpdateColumn()
{
}
}
}
这是您需要登录的主页。我从数据库中读取数据。问题是，当我多次按下出价按钮时，它只是重置，但在后台正在进行中。我需要做什么？
<Window x:Class="Auction.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="500" Width="800">
<Grid Margin="0,148,0,3" Name="myGrid" Background="#FF00286E">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="29*"/>
<ColumnDefinition Width="15*"/>
<ColumnDefinition Width="0*"/>
</Grid.ColumnDefinitions>
<Grid HorizontalAlignment="Left" Height="66" Margin="0,-68,0,0" VerticalAlignment="Top"
Width="792" Background="#FF00286E" Grid.ColumnSpan="2">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="12*"/>
<ColumnDefinition Width="13*"/>
</Grid.ColumnDefinitions>
<Button Content="Login" HorizontalAlignment="Left" Margin="10,10,0,0" VerticalAlignment="Bottom"
Width="102" Height="35" Name="btnLogin" Click="btnLogin_Click">
<Button.Template>
<ControlTemplate TargetType="Button">
<TextBlock TextDecorations="Underline" Margin="0,0,0,-19" FontSize="24"
FontFamily="Verdana" FontWeight="Bold" FontStyle="Italic">
<ContentPresenter />
</TextBlock>
</ControlTemplate>
</Button.Template>
</Button>
<Button Content="Logout" Grid.Column="1" HorizontalAlignment="Left" Margin="300,10,0,0" VerticalAlignment="Bottom"
Width="102" Height="35" Name="btnLogout" Click="btnLogout_Click">
<Button.Template>
<ControlTemplate TargetType="Button">
<TextBlock TextDecorations="Underline" Margin="0,0,0,-19" FontSize="24"
FontFamily="Verdana" FontWeight="Bold" FontStyle="Italic">
<ContentPresenter />
</TextBlock>
</ControlTemplate>
</Button.Template>
</Button>
</Grid>
<Grid HorizontalAlignment="Left" Height="78" Margin="0,-146,0,0" VerticalAlignment="Top" Width="792"
Grid.ColumnSpan="2" Background="#FF98BFD4">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="769*"/>
<ColumnDefinition Width="31*"/>
</Grid.ColumnDefinitions>
<Label Content="Welcome to Auction Application. Please Login to bid!" HorizontalAlignment="Center" Margin="44,28,0,0" VerticalAlignment="Top"
Height="40" Width="748" BorderThickness="3" FontSize="18" FontWeight="Bold" FontFamily="Verdana" Background="#FF98BFD4" Grid.ColumnSpan="2"/>
</Grid>
<Button Content="Bid" Grid.Column="1" HorizontalAlignment="Left" Margin="10,10,0,0"
VerticalAlignment="Top" Width="103" Height="29" FontSize="20" FontFamily="Verdana" FontStyle="Italic"
FontWeight="ExtraBold" Click="Button_Click" Name="btnBid"/>
<Button Content="Add User" Grid.Column="1" HorizontalAlignment="Left" Margin="10,255,0,0"
VerticalAlignment="Top" Width="103" Height="31" Name="btnAdd" Click="btnAdd_Click"/>
<DataGrid HorizontalAlignment="Left" Margin="10,10,0,0" VerticalAlignment="Top"
Height="298" Width="502" Name="dataGrid1" ItemsSource="{Binding}"
SelectionChanged="DataGrid_SelectionChanged" AlternatingRowBackground="Coral">
</DataGrid>
<TextBox Grid.Column="1" HorizontalAlignment="Left" Height="48" Margin="10,119,0,0" TextWrapping="Wrap"
VerticalAlignment="Top" Width="144" Name="tb" FontSize="20" FontWeight="Bold" FontStyle="Italic" IsReadOnly="True"/>
</Grid>
</Window>
答案 0 :(得分：0)
如果我理解正确，每次用户点击“出价”按钮时，您需要重置计时器。但是，之前的计时器仍在继续。我没有将您的代码粘贴到要测试的项目中，但在我看来，您需要使调度计时器成为类字段或属性，如下所示：
private DispatchTimer _dt = new System.Windows.Threading.DispatcherTimer();
在Bid的事件处理程序中，首先停止当前的_dt，然后实例化新的计时器：
_dt.Stop();
_dt = new System.Windows.Threading.DispatcherTimer();
尝试此更改：
namespace Auction
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
//Class level field:
private DispatchTimer _dt = new System.Windows.Threading.DispatcherTimer();
public MainWindow()
{
InitializeComponent();
GetData("SELECT * FROM Produs");
btnLogout.Visibility = System.Windows.Visibility.Hidden;
btnAdd.Visibility = System.Windows.Visibility.Hidden;
btnBid.Visibility = System.Windows.Visibility.Hidden;
tb.Visibility = System.Windows.Visibility.Hidden;
}
private void GetData(string SelectCommand)
{
SqlConnection conn = new SqlConnection(@"Data Source=ISAAC;Initial Catalog=licitatie;Integrated Security=True");
conn.Open();
SqlCommand cmd = new SqlCommand(SelectCommand);
cmd.Connection = conn;
SqlDataAdapter sda = new SqlDataAdapter(cmd);
DataTable dt = new DataTable("prod");
sda.Fill(dt);
myGrid.DataContext = dt;
}
private void btnLogin_Click(object sender, RoutedEventArgs e)
{
Login login = new Login();
login.Show();
Close();
}
private void Button_Click(object sender, RoutedEventArgs e)
{
Countdown(30, TimeSpan.FromSeconds(1), cur => tb.Text = cur.ToString());
}
void Countdown(int count, TimeSpan interval, Action<int> ts)
{
this._dt.Stop();
this._dt = new System.Windows.Threading.DispatcherTimer();
this._dt.Interval = interval;
this._dt.Tick += (_, a) =>
{
if (count-- == 0)
{
MessageBox.Show("You have won this product!");
this._dt.Stop();
}
else
ts(count);
};
ts(count);
this._dt.Start();
}
private void btnLogout_Click(object sender, RoutedEventArgs e)
{
MainWindow main = new MainWindow();
main.Show();
Close();
MessageBox.Show("You are not logged. Please log in to bid", "Failed",
MessageBoxButton.OK, MessageBoxImage.Information);
}
private void btnAdd_Click(object sender, RoutedEventArgs e)
{
Register reg = new Register();
reg.Show();
Close();
}
private void DataGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
var grid = sender as DataGrid;
var selected = grid.SelectedItem;
if (selected == grid.SelectedItem)
{
btnBid.Visibility = System.Windows.Visibility.Visible;
}
}
private void UpdateColumn()
{
}
}
}