Cascading drop downs

  
  

a!formLayout(
  label: "Create Incident Management",
  contents: {
    a!boxLayout(
      label: "Requestor Details",
      contents: {
        a!columnsLayout(
          columns: {
            a!columnLayout(
              contents: {
                a!textField(
                  label: "Requestor",
                  labelPosition: "ABOVE",
                  value: loggedInUser(),
                  saveInto: {},
                  refreshAfter: "UNFOCUS",
                  readOnly: true(),
                  validations: {}
                )
              }
            ),
            a!columnLayout(
              contents: {
                a!textField(
                  label: "Designation",
                  labelPosition: "ABOVE",
                  value: "Project Lead",
                  saveInto: {},
                  refreshAfter: "UNFOCUS",
                  readOnly: true(),
                  validations: {}
                )
              }
            )
          }
        )
      },
      style: "ACCENT"
    ),


   ri!subCategory: choose(
      if(isnull(ri!category),1,ri!category),
      {"Laptop Issue","Internet Issue"},
      {"Cabs Issue","AC Issue"},
      {"Salary Issue","Project Allocation Issue"},
      {"Finance Planning","Fund Raising"}
    ),
    
    a!sectionLayout(
      label: "Incident Category",
      contents: {
        a!columnsLayout(
          columns: {
            a!columnLayout(
              contents: {
                a!dropdownField(
                  label: "Category",
                  labelPosition: "ABOVE",
                  placeholder: "--- Select a Value ---",
                  choiceLabels: {"IT Support", "Admin Support", "HR Support", "Finance"},
                  choiceValues: {1,2,3,4},
                  value : ri!category,
                  saveInto:{
                    ri!category,
                    a!save(ri!subCategory, null)

                  }
                  /*searchDisplay: "AUTO",*/
                  /*validations: {}*/
                )
              }
            ),
            a!columnLayout(
              contents: {
                a!dropdownField(
                  label: "Sub Category",
                  labelPosition: "ABOVE",
                  placeholder: "--- Select a Value ---",
                  choiceLabels:ri!subCategory,

                  choiceValues:{1},
                  value: ri!subCategory,
                  saveInto:{ri!subCategory},
                  disabled: isnull(ri!category),
                  searchDisplay: "AUTO",
                  validations: {}
                )
              }
             
           ),
            a!columnLayout(
              contents: {
                a!dateTimeField(
                  label: "Reporting Date and Time",
                  labelPosition: "ABOVE",
                  value: ri!reportingDateTime,
                  saveInto: ri!reportingDateTime,
                  validations: {}
                )
              }
            )
          }
        ),
        a!cardLayout(
          contents: {
            a!columnsLayout(
              columns: {
                a!columnLayout(
                  contents: {
                    a!textField(
                      label: "Incident Title",
                      labelPosition: "ABOVE",
                      value : ri!incidentTitle,
                      saveInto: {ri!incidentTitle},
                      refreshAfter: "UNFOCUS",
                      validations: {}

                    )
                  }
                ),
                a!columnLayout(
                  contents: {
                    a!paragraphField(
                      label: "Description",
                      labelPosition: "ABOVE",
                      value: ri!Description,
                      saveInto: ri!Description,
                      refreshAfter: "UNFOCUS",
                      height: "MEDIUM",
                      validations: {}
                    )
                  }
                )
              }
            )
          },
          height: "AUTO",
          style: "SUCCESS",
          marginBelow: "STANDARD",
          showBorder: false()
        )
      }
    ),
    a!boxLayout(
      label: "SLA",
      style: "ACCENT"
    )
  },
  buttons: a!buttonLayout(
    primaryButtons: {
      a!buttonWidget(
        label: "Submit",
        submit: true,
        style: "PRIMARY"
      )
    },
    secondaryButtons: {
      a!buttonWidget(
        label: "Cancel",
        value: true,
        saveInto: ri!cancel,
        submit: true,
        style: "NORMAL",
        validate: false
      )
    }
  )
)

Could not display interface. Please check definition and inputs. Interface Definition: Expression evaluation error at function a!formLayout [line 7]: