我知道如何在寫作時讓文字消失：我們應該使用GotFocus LostFocus. 對于我這樣做的例子TextBox：
<TextBox x:Name="SearchNotes" Foreground="Gray"
Text="Search" LostFocus="NoteBox_OnLostFocus"
GotFocus="NoteBox_GotFocus" BorderThickness="0"
Background="WhiteSmoke" TextChanged="TextBox_TextChanged"
Width="771"
/>
這是代碼：
public void NoteBox_GotFocus(object sender, RoutedEventArgs e)
{
SearchNotes.Text = "";
SearchNotes.Foreground = Brushes.White;
}
public void NoteBox_OnLostFocus(object sender, RoutedEventArgs e)
{
SearchNotes.Text = "Search";
SearchNotes.Foreground = Brushes.Gray;
}
現在，我正在嘗試對另一個做同樣的事情TextBox，但問題是它TextBox在Window模板中，所以我無法TextBox從代碼中訪問它（或者我不知道如何訪問它）
這是 XAML 代碼：
<TextBox x:Name="WindowTextbox" GotFocus="WindowTextbox_GotFocus" LostFocus="WindowTextbox_LostFocus" Text="Type..." TextChanged="WindowTextbox_TextChanged" FontSize="15" Foreground="White" TextWrapping="Wrap" VerticalScrollBarVisibility="Auto" AcceptsReturn="True" Background="#404040" BorderThickness="0" Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="3" Grid.RowSpan="3" Margin="0 0 0 23">
</TextBox>
當我試圖從代碼中訪問它時，我不能：
所以我想知道如何處理這個問題。
uj5u.com熱心網友回復：
這就是sender引數的用途，請參閱Routed Events Overview。
呼叫處理程式的物件是
sender引數報告的物件。
private void WindowTextbox_GotFocus(object sender, RoutedEventArgs e)
{
var textBox = (TextBox)sender;
textBox.Text = "";
textBox.Foreground = Brushes.White;
}
private void WindowTextbox_LostFocus(object sender, RoutedEventArgs e)
{
var textBox = (TextBox)sender;
textBox.Text = "Search";
textBox.Foreground = Brushes.Gray;
}
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