QT creator Cannot open source file

[baijiaheizhiganmao]

Hi all：
I just create a GUI project in a choosed path (windows system),befor add any code in this project ,I clicked the button:Run,only to find this error :Cannot open file:'.\main.cpp':No such file or directory .But actually it has such a file:created by the Qt itself ! so How Could I fix this issue ? thank you !
ps：this issue hasn't occured when I use VS to create a same QT GUI project.

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大家好：
我使用qt creator 创建了一个GUI的工程，工程路径是自己制定的，使用windows 系统。建立好了之后，我运行，发现他弹出这个错误提示：Cannot open file:'.\main.cpp':No such file or directory。事实上这是Qt自己完成的，我没有改动任何东西。请问我应该如何修改这个问题，谢谢。
ps：我用vs建立Qt工程没有出现这个问题，两者使用的是同一个qt。

[dheerendra]

what type of project you created ? Do you see the main.cpp in Project explorer on the left side of your Qt creator ? Can you create new project and try ? Can you clean, run the qmake again and give build ?

[baijiaheizhiganmao]

@Dheerendra Dheerendra
project type：Qt4 Gui Application
I can see the main.cpp
I can create new project but can't run as the same reason;
I can clean and qmake that pro.,but when run it ,give me the error msg :
Cannot find source file ：‘.\main.cpp’ No such file or directory
Cannot find source file ：‘.\mainwindow.cpp’ No such file or directory

the project name is testAgain,in that *.pro file I can see the info.as belowe:
#---------------------------------------------

project cerate by Qt Creator 2014-09-05t09:53:21

#---------------------------------------------
TARGET = testAgain
TEMPLATE = app
SOURCES += main.cpp
mainwindow.cpp
HEADERS += mainwindow.h
FORM += mainwindow.ui

so you can see I haven't change anyting before add my owner code to this project ,it just cannot work.
The strange is ,if I use VS to create the same Qt project ,nothing go wrong ! But I need to use Qt creator in a straightway > _ <