使用反射作为接口类型的设置值

Question

I have a map with value of type interface.Also I want to use this map key,val for change value in another func with reflect.

    func main(){
        ValueForUpdate := make(map[string]interface{})
        ValueForUpdate["DeliveryCount"] = 2 //type int
        ValueForUpdate["BulkId"] = "100200300"  //type string

        UpdateSendTBL(ValueForUpdate)
    }

    func UpdateSendTBL(keyNewVal map[string]interface{}){
        get := // some data
        rowValue := reflect.ValueOf(get).Elem()
        for key, val := range keyNewVal {
            fieldValue := rowValue.FieldByName(key)
            if fieldValue.Type().String() == "string" {
                fieldValue.SetString(val)
            }else if fieldValue.Type().String() == "int"{
                fieldValue.SetInt(val)
            }

        }
    }

but this error :

cannot use val (type interface {}) as type int64 in argument to fieldValue.SetInt: need type assertion

cannot use val (type interface {}) as type string in argument to fieldValue.SetString: need type assertion

Answer 1

You need to make use of type assertion, change the code as below:

    if fieldValue.Type().String() == "string" {
        fieldValue.SetString(val.(string))
    }else if fieldValue.Type().String() == "int"{
        fieldValue.SetInt(val.(int64))
    }