C#使用FileStream和StreamWriter写入文件时出现文件被其他程序占用的异常，求大神指点。

if ((ProjectInPath + "/Project/ProjectName/ProjectNameRead.LMPN"))

 {

 String ProjectNameWrite = (ProjectInPath + "/Project/ProjectName/ProjectNameRead.LMPN");

 FileStream fs_sw = new FileStream(ProjectInPath + "/Project/ProjectName/ProjectNameRead.LMPN", FileMode.Create );

 StreamWriter sw_fs = new StreamWriter(fs_sw);

 if(ProjectNameWrite == "")

 {

 sw_fs.Write(ProjectName);

 }

 else

 {

 sw_fs.Write(ProjectNameWrite + Environment.NewLine + ProjectName);

 }

 sw_fs.Flush();

 sw_fs.Close();

 fs_sw.Close();

 FileStream FS = new FileStream(ProjectInPath + "/Project/ProjectPath/" + ProjectName + ".LMPP",FileMode.Create);

 StreamWriter SW = new StreamWriter(FS);

 SW.Write("DefaultProjectPath");

 SW.Flush();

 SW.Close();

 FS.Close();

 FileStream FSSW = new FileStream(ProjectInPath + "/Project/ProjectDate/" + ProjectName + ".LMPD",FileMode.Create);

 StreamWriter SWFS = new StreamWriter(FSSW);

 SWFS.Write(CreateDate);

 SWFS.Flush();

 SWFS.Close();

 FSSW.Close();

 FileStream fs_LastOpenTime = new FileStream(ProjectInPath + "/Project/LastOpenTime/" + ProjectName + ".LMLOT", FileMode.Create);

 StreamWriter sw_LastOpenTime = new StreamWriter(fs_LastOpenTime);

 sw_LastOpenTime.Write(System.DateTime.Now.ToString());

 sw_LastOpenTime.Flush();

 sw_LastOpenTime.Close();

 fs_LastOpenTime.Close();

 FileStream fs_FinallyOpenProject = new FileStream(ProjectInPath + "/Project/FinallyOpenProject/FinallyOpenProject.LMFOP", FileMode.Create);

 StreamWriter sw_FinallyOpenProject = new StreamWriter(fs_FinallyOpenProject);

 sw_FinallyOpenProject.Write(ProjectName);

 sw_FinallyOpenProject.Flush();

 sw_FinallyOpenProject.Close();

 fs_FinallyOpenProject.Close();

 return true;

 }

 else

 {

 return false;

 }

String line = String.Empty;
                        int IfProjectNameSave = 0;
                        using (StreamReader reader = new StreamReader(SC.GetInPath() + "/Project/ProjectName/ProjectNameRead.LMPN"))
                        {
                            line = reader.ReadLine();
                            while(line != null && line != "")
                            {
                                if(TextBox_项目名称.Text == line)
                                {
                                    MessageBox.Show("已存在相同项目名的项目！", "提示");
                                    IfProjectNameSave = 1;
                                    break;
                                }else
                                {
                                    IfProjectNameSave = 2;
                                }
                                line = reader.ReadLine();
                            }
                            if((SC.GetInPath() + "/Project/ProjectName/ProjectNameRead.LMPN") == "")
                            {
                                IfProjectNameSave = 2;
                            }
                            if(IfProjectNameSave == 2)
                            {
                                String ProjectType = String.Empty;
                                String CompileType = String.Empty;
                                Boolean IfCreateProject;
                                if(RadioButton_Windos.Checked)
                                {
                                    ProjectType = "Windows";
                                }
                                if(RadioButton_解释编写.Checked)
                                {
                                    CompileType = "脚本编译";
                                }
                                if((SC.GetInPath() + "/Project/DefaultProjectPath/" + TextBox_项目名称.Text + ".LMP"))
                                {
                                    MessageBox.Show("存储路径下有着相同的项目文件，程序将默认为覆盖此项目文件！", "警告");
                                    File.Delete(SC.GetInPath() + "/Project/DefaultProjectPath/" + TextBox_项目名称.Text + ".LMP");
                                    IfCreateProject = SC.CreateProject(TextBox_项目名称.Text, ProjectType, System.DateTime.Now.ToString(), CompileType, SC.GetInPath());
                                    if (IfCreateProject)
                                    {
                                        SC.InEdit();
                                    }
                                    else
                                    {
                                        MessageBox.Show("项目创建失败，请到官网查看解决方法！", "提示");
                                    }

                                }
                                else
                                {
                                    IfCreateProject = SC.CreateProject(TextBox_项目名称.Text, ProjectType, System.DateTime.Now.ToString(), CompileType, SC.GetInPath());
                                    if (IfCreateProject)
                                    {
                                        SC.InEdit();
                                    }
                                    else
                                    {
                                        MessageBox.Show("项目创建失败，请到官网查看解决方法！", "提示");
                                    }
                                }
                            }
                            reader.Close();
                        }