R Shiny Dashboard：无法创建Box

Question

我正在尝试在Shiny Dashboard侧边栏中包含一个文件输入，并在仪表板主体中包含一个框，尽管我多次尝试，但只要我的文件输入位于补充工具栏中，我就无法在仪表板主体中看到任何框。每一个帮助都很重要。再次感谢。

以下是1个示例代码

#UI   
library(shinydashboard)

dashboardPage(
 dashboardHeader(title= "my dashboard"),
  dashboardSidebar(width=250,
   sidebarMenu(
    menuItem("Data UpLoad", tabName = "dashboard", icon = icon("table"),
        fileInput('file1','Choose CSV File',
                  accept=c('text/csv','text/comma-separated-values,text/plain', '.csv'))),
    menuItem("Widgets", tabName = "widgets", icon = icon("th"))
  )),
dashboardBody(
 tabItems(
 #first tab content
 tabItem(tabName="dashboard",
  fluidRow(
   box(title="Data",solidHeader = TRUE, collapsible = 
    TRUE,tableOutput("table1"))
      )
      ),
 tabItem(tabName="widgets")))
  )

#server

library(shiny)
library(shinydashboard)
library(dplyr)


server <- function(input, output) {
output$table1= renderTable({
  inFile=input$file1

 if(is.null(inFile))
return(NULL)
read.csv(inFile$datapath)
 })
 }