DllImport("User32")] 
private extern static int GetWindow(int hWnd, int wCmd); 

[DllImport("User32")] 
private extern static int GetWindowLongA(int hWnd, int wIndx); 

[DllImport("user32", CharSet = CharSet.Auto)] 
private extern static int GetWindowTextLength(IntPtr hWnd); 

[DllImport("user32.dll")] 
private static extern bool GetWindowText(int hWnd, StringBuilder title, int maxBufSize); 

private const int GW_HWNDFIRST = 0; 
private const int GW_HWNDNEXT = 2; 
private const int GWL_STYLE = (-16); 
private const int WS_VISIBLE = 268435456; 
private const int WS_BORDER = 8388608; 

public List <string> GetRunApplicationList(Form appForm) 
{ 
    try 
    { 
        List <string> appString = new List <string>(); 
        int handle = (int)appForm.Handle; 
        int hwCurr; 
        hwCurr = GetWindow(handle, GW_HWNDFIRST); 
        while (hwCurr > 0) 
        { 
            int isTask = (WS_VISIBLE | WS_BORDER); 
            int lngStyle = GetWindowLongA(hwCurr, GWL_STYLE); 
            bool taskWindow = ((lngStyle & isTask) == isTask); 
            if (taskWindow) 
            { 
                int length = GetWindowTextLength(new IntPtr(hwCurr)); 
                StringBuilder sb = new StringBuilder(2 * length + 1); 
                GetWindowText(hwCurr, sb, sb.Capacity); 
                string strTitle = sb.ToString(); 
                if (!string.IsNullOrEmpty(strTitle)) 
                { 
                    appString.Add(strTitle); 
                } 
            } 
            hwCurr = GetWindow(hwCurr, GW_HWNDNEXT); 
        } 
        return appString; 
    } 
    catch (Exception ex) 
    { 
        throw new ApplicationInfoException("读取应用程序信息时出错：" + ex.Message); 
    } 
}

------解决方案--------------------
进程.MainWindowTitle不是应用程序名吗
我做过一个简单的任务管理器，能得到应用程序名的