这个例子是从 水如烟的例子 修改过来的。如有不妥之处还请大家指正批评。
imports system.threading
imports system.runtime.compilerservices
public class frmcmdexcute
 inherits system.windows.forms.form
#region " windows 窗体设计器生成的代码 "
 public sub new()
 mybase.new()
 '该调用是 windows 窗体设计器所必需的。
 initializecomponent()
 '在 initializecomponent() 调用之后添加任何初始化
 end sub
 '窗体重写 dispose 以清理组件列表。
 protected overloads overrides sub dispose(byval disposing as boolean)
 if disposing then
 if not (components is nothing) then
 components.dispose()
 end if
 end if
 mybase.dispose(disposing)
 end sub
 'windows 窗体设计器所必需的
 private components as system.componentmodel.icontainer
 '注意: 以下过程是 windows 窗体设计器所必需的
 '可以使用 windows 窗体设计器修改此过程。
 '不要使用代码编辑器修改它。
 friend withevents tbresult as system.windows.forms.textbox
 friend withevents panel1 as system.windows.forms.panel
 friend withevents btnexcute as system.windows.forms.button
 friend withevents label1 as system.windows.forms.label
 friend withevents btclear as system.windows.forms.button
 friend withevents tbcomtext as system.windows.forms.combobox
 <system.diagnostics.debuggerstepthrough()> private sub initializecomponent()
 me.tbresult = new system.windows.forms.textbox
 me.panel1 = new system.windows.forms.panel
 me.tbcomtext = new system.windows.forms.combobox
 me.btclear = new system.windows.forms.button
 me.label1 = new system.windows.forms.label
 me.btnexcute = new system.windows.forms.button
 me.panel1.suspendlayout()
 me.suspendlayout()
 '
 'tbresult
 '
 me.tbresult.anchor = ctype((((system.windows.forms.anchorstyles.top or system.windows.forms.anchorstyles.bottom) _
 or system.windows.forms.anchorstyles.left) _
 or system.windows.forms.anchorstyles.right), system.windows.forms.anchorstyles)
 me.tbresult.backcolor = system.drawing.systemcolors.info
 me.tbresult.borderstyle = system.windows.forms.borderstyle.fixedsingle
 me.tbresult.location = new system.drawing.point(8, 8)
 me.tbresult.multiline = true
 me.tbresult.name = "tbresult"
 me.tbresult.scrollbars = system.windows.forms.scrollbars.both
 me.tbresult.size = new system.drawing.size(584, 304)
 me.tbresult.tabindex = 0
 me.tbresult.text = ""
 '
 'panel1
 '
 me.panel1.anchor = ctype((system.windows.forms.anchorstyles.bottom or system.windows.forms.anchorstyles.right), system.windows.forms.anchorstyles)
 me.panel1.controls.add(me.tbcomtext)
 me.panel1.controls.add(me.btclear)
 me.panel1.controls.add(me.label1)
 me.panel1.controls.add(me.btnexcute)
 me.panel1.location = new system.drawing.point(8, 320)
 me.panel1.name = "panel1"
 me.panel1.size = new system.drawing.size(584, 40)
 me.panel1.tabindex = 1
 '
 'tbcomtext
 '
 me.tbcomtext.location = new system.drawing.point(224, 8)
 me.tbcomtext.name = "tbcomtext"
 me.tbcomtext.size = new system.drawing.size(224, 20)
 me.tbcomtext.tabindex = 5
 me.tbcomtext.text = "dir"
 '
 'btclear
 '
 me.btclear.flatstyle = system.windows.forms.flatstyle.flat
 me.btclear.location = new system.drawing.point(40, 8)
 me.btclear.name = "btclear"
 me.btclear.size = new system.drawing.size(80, 24)
 me.btclear.tabindex = 3
 me.btclear.text = "清空(&c)"
 '
 'label1
 '
 me.label1.location = new system.drawing.point(160, 8)
 me.label1.name = "label1"
 me.label1.size = new system.drawing.size(48, 16)
 me.label1.tabindex = 2
 me.label1.text = "命令:"
 '
 'btnexcute
 '
 me.btnexcute.flatstyle = system.windows.forms.flatstyle.flat
 me.btnexcute.location = new system.drawing.point(472, 8)
 me.btnexcute.name = "btnexcute"
 me.btnexcute.size = new system.drawing.size(80, 24)
 me.btnexcute.tabindex = 1
 me.btnexcute.text = "执行(&e)"
 '
 'frmcmdexcute
 '
 me.acceptbutton = me.btnexcute
 me.autoscalebasesize = new system.drawing.size(6, 14)
 me.clientsize = new system.drawing.size(600, 365)
 me.controls.add(me.panel1)
 me.controls.add(me.tbresult)
 me.name = "frmcmdexcute"
 me.text = "command excute result"
 me.panel1.resumelayout(false)
 me.resumelayout(false)
 end sub
#end region
 public shared sub main()
 if system.environment.osversion.tostring.indexof("nt") = -1 then
 msgbox("暂时不支持非nt系统,程序退出!")
 application.exit()
 else
 application.run(new frmcmdexcute)
 end if
 end sub
 private delegate sub textaddhandler(byval strpara as string)
#region "private viable"
 dim sw as io.streamwriter
 dim sr as new mystreamreader
 dim err as new mystreamreader
 dim p as system.diagnostics.process = new system.diagnostics.process
 dim psi as new system.diagnostics.processstartinfo(system.environment.getenvironmentvariable("comspec"))
#end region
 private sub frmcmdexcute_load(byval sender as system.object, byval e as system.eventargs) handles mybase.load
 p = new system.diagnostics.process
 '"cmd.exe"为nt的命令行程序
 psi = new system.diagnostics.processstartinfo("cmd.exe")
 psi.useshellexecute = false
 psi.redirectstandardinput = true
 psi.redirectstandardoutput = true
 psi.redirectstandarderror = true
 psi.createnowindow = true
 p.startinfo = psi
 p.start()
 sw = p.standardinput
 sr.stream = p.standardoutput
 err.stream = p.standarderror
 sw.autoflush = true
 sr.stream.basestream.beginread(sr.bytes, 0, 1024, new asynccallback(addressof cbstream), sr)
 err.stream.basestream.beginread(err.bytes, 0, 1024, new asynccallback(addressof cbstream), err)
 end sub
 private sub frmcmdexcute_closed(byval sender as object, byval e as system.eventargs) handles mybase.closed
 p.close()
 if not sw is nothing then
 sw.close()
 end if
 if not sr is nothing then
 sr.stream.close()
 end if
 if not err is nothing then
 err.stream.close()
 end if
 end sub
 private sub btclear_click(byval sender as system.object, byval e as system.eventargs) handles btclear.click
 me.tbresult.text = string.empty
 end sub
 private sub btnexcute_click(byval sender as system.object, byval e as system.eventargs) handles btnexcute.click
  me.cmdexcute()
 end sub
 private sub cmdexcute()
 try
 me.cursor = system.windows.forms.cursors.waitcursor
 if me.tbcomtext.text <> "" then
 sw.writeline(me.tbcomtext.text)
 else
 sw.writeline("dir")
 end if
 me.cursor = system.windows.forms.cursors.default
 '向combobox中添加元素
 me.tbcomtext.items.add(me.tbcomtext.text)
 me.tbcomtext.selectionstart = 0
 me.tbcomtext.selectionlength = me.tbcomtext.text.length
 me.tbcomtext.focus()
 catch ex as exception
 msgbox("cmdexcute--" & ex.tostring)
 end try
 end sub
 private sub apptext(byval stradd as string)
 me.tbresult.text &= stradd
 end sub
 '回调函数
 '为了保证执行invoke方法的线程顺序,使用了methodimpl
 <methodimpl(methodimploptions.synchronized)> _
 sub cbstream(byval s as iasyncresult)
 try
 dim t as mystreamreader = ctype(s.asyncstate, mystreamreader)
 if t.stream.basestream is nothing then
 exit sub
 end if
 dim i as integer = t.stream.basestream.endread(s)
 dim strreceive as string = system.text.encoding.default.getstring(t.bytes, 0, i)
 me.invoke(new textaddhandler(addressof apptext), new object() {strreceive})
 t.stream.basestream.beginread(t.bytes, 0, 1024, new asynccallback(addressof cbstream), t)
 catch ex as exception
 msgbox("cbstream--" & ex.tostring)
 end try
 end sub
 friend class mystreamreader
 public stream as io.streamreader
 public bytes(1024) as byte
 public sub new()
 end sub
 end class
end class