Inputs of Shiny are not holding values. They get resetted to initial values. Used isolate() function too. Using renderUI() & updateSelectInput() in the app.

[prateek26394]

Ui.R file is

ui<-fluidPage(
  
fluidRow(

  tags$h5("Inputs",style="color:red"),
  tags$em(column(2,selectInput("table Type","Table",choices = c("TableA","TableB","TableC"))),style="color:blue"),
  tags$em(column(2,uiOutput("Part ID")),style="color:blue")
),

fluidRow(
  
  tags$em(tags$h5("Parts Data",style="color:red")),
  column(5,dataTableOutput("table1"))
  
  
)
)

The server.R file is

server <- function(input, output,session) {
 observe({
  
    if(input$`table Type`=="A"){
   
     output$`Part ID`<-renderUI(selectInput("PartsID","Part ID",choices = TableA$PartsID)) 
     
     Table1<-subset(Input_Table,PartsID==input$PartsID)
    
      output$table1<-renderDataTable(table1)
     
     }
  })

observe({
    if(input$`table Type`=="B"){
      
      output$`Part ID`<-renderUI(selectInput("PartsID","Part ID",choices = TableB$PartsID))  

      Table2<-subset(TableB,PartsID==input$PartsID)    
      output$table1<-renderDataTable(Table2)
  }
  
    })


observe({
    if(input$`table Type`=="C"){
      
      output$`Part ID`<-renderUI(selectInput("PartsID","Part ID",choices = TableC$PartsID))  

      Table3<-subset(TableC,PartsID==input$PartsID)    
      output$table1<-renderDataTable(Table3)
  }
  
    })
}

Global.R file contains

library(shiny)
library(DT)        
library(openxlsx)  
library(dplyr)

TableA<-read.xlsx("…\\Table.xlsx,sheet"=1,startRow=1,colnames=TRUE)
TableB<-read.xlsx("…\\Table.xlsx",sheet=2,startRow=1,colnames=TRUE)
TableC<-read.xlsx("…\\Table.xlsx,sheet"=3,startRow=1,colnames=TRUE)

The problem I am facing is that on selecting PartID from input the output table is generated for 1 second and then PartID gets reset to initial value.

I have tried updating the server.R file
instead renderUi I have used updateselectinput.
changed Observe() to ObserveEvent(input$Part ID{...})
used isolate() different places.
Like

output$`Part ID`<-renderUI(isolate(selectInput("PartsID","Part ID",choices = TableC$PartsID)) )

or,

observe({ isolate({
    if(input$`table Type`=="C"){
      
      output$`Part ID`<-renderUI(selectInput("PartsID","Part ID",choices = TableC$PartsID))  

      Table3<-subset(TableC,PartsID==input$PartsID)    
      output$table1<-renderDataTable(Table3)
  }
})

# Here, Part ID input do not reset but the "table is not updated either".

and everywhere in the middle

What, am I doing wrong.

I am still learning Observe(), ObserveEvent() & isolate() functions, they are pretty new for me.

Thanking you for your time and concern.