WPF好像没有自带的文字提示漂浮，我们可以定制一个。

效果如下：

xaml

xaml如下：

<Window x:Class="GroupServer.MsgTip"
        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:GroupServer"
        mc:Ignorable="d"
        Title="MsgTip" ResizeMode="NoResize" Background="#00FFFFFF" AllowsTransparency="True" SizeToContent="WidthAndHeight" Topmost="True" ShowInTaskbar="False" WindowStyle="None" Loaded="Window_Loaded">
    <Border  Background="#91d024" CornerRadius="10" >
        <Label x:Name="labTxt" Margin="20"   HorizontalContentAlignment="Center" VerticalContentAlignment="Center" FontSize="18">这是一个消息提示框</Label>
    </Border>
</Window>

这里SizeToContent是适配窗口大小，Topmost是置顶，CornerRadius是圆角。

cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

namespace GroupServer
{
    /// <summary>
    /// MsgTip.xaml 的交互逻辑
    /// </summary>
    public partial class MsgTip : Window
    {
        public MsgTip()
        {
            InitializeComponent();
        }

        public void ShowTxt(string msg, int delaytime = 3000)
        {
            labTxt.Content = msg;
            Show();
            _ = DelayClose(msg, delaytime);
        }

        async Task DelayClose(string msg,int delaytime = 3000)
        {
            await Task.Delay(delaytime);
            Close();
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            MainWindow mainWindow = (MainWindow)Application.Current.MainWindow;
            this.Top = mainWindow.Top + (mainWindow.Height - Height) / 2;
            this.Left = mainWindow.Left + (mainWindow.Width - Width) / 2;
        }
    }
}

WindowLoad是为了让窗口在应用主界面中心显示
我们只要调用ShowTxt函数就可以了。

public static void ShowTip(string msg, int delaytime = 3000)
{
    MsgTip tip = new MsgTip();
    tip.ShowTxt(msg, delaytime);
}