当在 CustomTaskPane 控件中托管时，WebBrowser 或 WPF 控件在 Office 应用程序中无法正确显示内容

2024-03-13
适用于: Office Products, Outlook Development, Outlook 2019, Outlook 2016, Outlook 2013, Outlook 2010

原始 KB 编号： 4490421

症状

在某些情况下，当控件托管在 CustomTaskPane 控件或 Outlook FormRegion 中时，WebBrowser 或 WPF 控件内容可能无法在 Microsoft Office 应用程序中显示或正常运行。

原因

这些问题可能是由主机应用程序未将焦点返回到控件内呈现的 HTML 元素，或者由 Microsoft Office 解决方案中的高 DPI 和 DPI 缩放导致，如处理 Microsoft Office 解决方案中的高 DPI 和 DPI 缩放一文中所述。

解决方法 1：高 DPI 和 DPI 缩放问题

将名为的 NativeImports 类添加到代码中，如下所示，并将以下行添加到 ThisAddIn_Startup 方法：

NativeImports.SetThreadDpiHostingBehavior(NativeImports.DPI_HOSTING_BEHAVIOR.DPI_HOSTING_BEHAVIOR_MIXED);

// ThisAddIn.cs

namespace TaskPaneWorkaround
{
    public partial class ThisAddIn
    {
        private MyUserControl myUserControl1;
        private Microsoft.Office.Tools.CustomTaskPane myCustomTaskPane;

        private void ThisAddIn_Startup(object sender, System.EventArgs e)
        {
            // Workaround for the rendering issues to do with DPI

NativeImports.SetThreadDpiHostingBehavior(NativeImports.DPI_HOSTING_BEHAVIOR.DPI_HOSTING_BEHAVIOR_MIXED);

            myUserControl1 = new MyUserControl();
            myCustomTaskPane = this.CustomTaskPanes.Add(myUserControl1, "My Task Pane");
            myCustomTaskPane.Visible = true;
        }

        private void ThisAddIn_Shutdown(object sender, System.EventArgs e)
        {
        }

        #region VSTO generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>

        private void InternalStartup()
        {
            this.Startup += new System.EventHandler(ThisAddIn_Startup);
            this.Shutdown += new System.EventHandler(ThisAddIn_Shutdown);
        }

        #endregion
    }
}


// NativeImports.cs

namespace TaskPaneWorkaround
{
    class NativeImports
    {

        internal enum DPI_HOSTING_BEHAVIOR
        {
            DPI_HOSTING_BEHAVIOR_INVALID = -1,
            DPI_HOSTING_BEHAVIOR_DEFAULT = 0,
            DPI_HOSTING_BEHAVIOR_MIXED = 1
        };

        [DllImport("user32.dll")]
        internal static extern DPI_HOSTING_BEHAVIOR SetThreadDpiHostingBehavior(DPI_HOSTING_BEHAVIOR value);

        [DllImport("user32.dll", SetLastError = true)]
        private static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);
    }

}

解决方法 2：主机应用程序未返回焦点的问题

在 CustomTaskPane 与实际 WebBrowser 或 WPF 控件之间添加中间窗体。

有关向应用程序添加自定义任务窗格的详细信息，请参阅向应用程序添加自定义任务窗格。

对于 WPF 呈现问题，解决方法包括在 WindowsForm 中托管 WPF UserControl，如演练：在 Windows 窗体中托管 3D WPF 复合控件中所述。

下面是实现此解决方法的名为 MyUserControl 的用户控件的示例：

将名为 MyUserControl的 UserControl 添加到外接程序。
修改 UserControl 的源代码，并声明 Load、Paint 和 Resize 事件处理程序，如以下示例所示。
将 Windows 窗体 添加到项目。将其命名 为 WorkaroundForm 并声明 Load 事件处理程序。
将 WebBrowser 控件添加到 WorkaroundForm ，如以下示例所示。

创建 CustomTaskPane 并向其添加 MyUserControl 的实例。

// ThisAddIn.cs

namespace TaskPaneWorkaround
{
    public partial class ThisAddIn
    {
        private MyUserControl myUserControl1;
        private Microsoft.Office.Tools.CustomTaskPane myCustomTaskPane;

        private void ThisAddIn_Startup(object sender, System.EventArgs e)
        {
            myUserControl1 = new MyUserControl();
            myCustomTaskPane = this.CustomTaskPanes.Add(myUserControl1, "My Task Pane");
            myCustomTaskPane.Visible = true;
        }

        private void ThisAddIn_Shutdown(object sender, System.EventArgs e)
        {
        }

        #region VSTO generated code
        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>

        private void InternalStartup()
        {
            this.Startup += new System.EventHandler(ThisAddIn_Startup);
            this.Shutdown += new System.EventHandler(ThisAddIn_Shutdown);
        }

        #endregion
    }
}

// MyUserControl.cs

using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace TaskPaneWorkaround
{
    public partial class MyUserControl : UserControl
    {
        bool isformdisplayed = false;
        WorkaroundForm workaroundForm;

        [DllImport("user32.dll", SetLastError = true)]
        private static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);

        public MyUserControl()
        {
            this.SuspendLayout();
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.Name = "MyUserControl";
            this.Paint += new System.Windows.Forms.PaintEventHandler(this.MyUserControl_Paint);
            this.Resize += new System.EventHandler(this.MyUserControl_Resize);
            this.ResumeLayout(false);

            this.Paint += MyUserControl_Paint;
            this.Resize += MyUserControl_Resize;
        }

        private void MyUserControl_Load(object sender, System.EventArgs e)
        {
           this.Paint += MyUserControl_Paint;
        }

        private void MyUserControl_Paint(object sender, PaintEventArgs e)
        {
            if (!isformdisplayed)
            {
                this.SuspendLayout();
                workaroundForm = new WorkaroundForm();
                SetParent(workaroundForm.Handle, this.Handle);
                workaroundForm.Dock = DockStyle.Fill;
                workaroundForm.Width = Width;
                workaroundForm.Height = Height;
                workaroundForm.Show();
                isformdisplayed = true;
                this.ResumeLayout();
            }
        }

        private void MyUserControl_Resize(object sender, EventArgs e)
        {
            if (isformdisplayed)
            {
                workaroundForm.Width = this.Width;
                workaroundForm.Height = this.Height;
            }
        }
    }
}

//WorkaroundForm.cs

using System;
using System.Drawing;
using System.Windows.Forms;

namespace TaskPaneWorkaround
{
    public partial class WorkaroundForm : Form
    {
        public WorkaroundForm()
        {
            this.SuspendLayout();
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(509, 602);
            this.Name = "Form1";
            this.Text = "Form1";
            this.Load += new System.EventHandler(this.WorkaroundForm_Load);
            this.ResumeLayout(false);
        }
        private void WorkaroundForm_Load(object sender, EventArgs e)
        {
            this.SuspendLayout();
            this.Location = new Point(0, 0);
            this.Dock = DockStyle.Fill;
            this.FormBorderStyle = FormBorderStyle.None;
            WebBrowser webBrowser = new WebBrowser();
            this.Controls.Add(webBrowser);
            webBrowser.Location = new Point(0, 0);
            webBrowser.Dock = DockStyle.Fill;
            this.ResumeLayout();
            webBrowser.Focus();
            webBrowser.Navigate(new System.Uri("https://bing.com"));
        }

    }
}

通过

当在 CustomTaskPane 控件中托管时，WebBrowser 或 WPF 控件在 Office 应用程序中无法正确显示内容

症状

原因

解决方法 1：高 DPI 和 DPI 缩放问题

解决方法 2：主机应用程序未返回焦点的问题

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