CLASS ViewWinForm
{

Private bool run;
Form oForm;

public ViewWinForm()
{
//构造函数
oForm=new Form();
oForm.FormClosed+=new ormClosedEventHandler(form_FormClosed);

}

public void view()
{
run = true;
form.Show();
while (run)
{
Application.DoEvents();
Thread.Sleep(1);
}
}

void form_FormClosed(object sender, FormClosedEventArgs e)
{
run = false;
}
}

SBO中显示模态窗体（如:对话框)
摘自https://www.sdn.sap.com/irj/sdn/thread?threadID=45710&tstart=0

After searching the forums for a way to reliably open an open file dialog I didn’t really find any examples showing what I needed. Anyway, here’s what I came up with.

There are two problems to deal with:

1. The dialog must be run on a separate thread.
2. The dialog must be modal for the CORRECT INSTANCE of the SAP client window.

With my item events I invoke the dialog with the following code example for an excel file. I was using the try/catch for debugging purposes.

I hope this helps someone out in the future.

GetFileNameClass oGetFileName = new GetFileNameClass();
oGetFileName.Filter = “Excel files (*.xls)|*.xls”;
oGetFileName.InitialDirectory =
Environment.GetFolderPath(Environment.SpecialFolder.Personal);
Thread threadGetExcelFile = new Thread(new ThreadStart(oGetFileName.GetFileName));
threadGetExcelFile.ApartmentState = ApartmentState.STA;
try
{
threadGetExcelFile.Start();
while (!threadGetExcelFile.IsAlive); // Wait for thread to get started
Thread.Sleep(1); // Wait a sec more
threadGetExcelFile.Join(); // Wait for thread to end

// Use file name as you will here
string strValue = oGetFileName.FileName;

}
catch(Exception ex)
{
_SBO_Application.MessageBox(ex.Message,1,”OK”,”",”");
}
threadGetExcelFile = null;
oGetFileName = null;

The following is my GetFileName class. More properties can be easily added like FileName, Filter, and InitialDirectory were. Change the namespace as appropriate.

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

namespace MyNamespace
{
///
/// Wrapper for OpenFileDialog
///
public class GetFileNameClass
{
[DllImport( "user32.dll" )]
private static extern IntPtr GetForegroundWindow();

OpenFileDialog _oFileDialog;

// Properties
public string FileName
{
get { return _oFileDialog.FileName; }
set { _oFileDialog.FileName = value; }
}

public string Filter
{
get { return _oFileDialog.Filter; }
set { _oFileDialog.Filter = value; }
}

public string InitialDirectory
{
get { return _oFileDialog.InitialDirectory; }
set { _oFileDialog.InitialDirectory = value; }
}

// Constructor
public GetFileNameClass()
{
_oFileDialog = new OpenFileDialog();
}

// Methods

public void GetFileName()
{
IntPtr ptr = GetForegroundWindow();
WindowWrapper oWindow = new WindowWrapper(ptr);
if (_oFileDialog.ShowDialog(oWindow) != DialogResult.OK)
{
_oFileDialog.FileName = string.Empty;
}
oWindow = null;
} // End of GetFileName
}
}

Edit: Changed namespace to “MyNamespace”

Whoops, I forgot the window wrapper:

using System;

namespace MyNamespace
{
public class WindowWrapper : System.Windows.Forms.IWin32Window
{
private IntPtr _hwnd;

// Property
public virtual IntPtr Handle
{
get { return _hwnd; }
}

// Constructor
public WindowWrapper(IntPtr handle)
{
_hwnd = handle;
}
}
}

来源: http://www.cnblogs.com/el-net/articles/1036863.html