How do check key already added to a hastable and their corresponding values

Question

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.NET3.5

C#

public static DateTime LoggedOn = DateTime.Now;

C#

Hashtable ht = new Hashtable();

hash.Add("Hello", LoggedOn);  // output like "Hello", 18.11.2016 09:52:07 
hash.Add("Hello", LoggedOn);   // output like "Hello", 18.11.2016 09:52:27 
hash.Add("Hello", LoggedOn);    // output like "Hello", 18.11.2016 09:52:55

bool htexists = ht.ContainsKey("Hello");
bool valueexists = ht.ContainsValue(LoggedOn);

if (htexists && valueexists)
{
//if it is first entry allow it 
//my first question it returns always true as i have addaded key and value to my ht but i want to check when it is added more than one time of not if first entry OK

// my second ?  how to check then correspondend value in my case with time  
//if same message say hello is added within few minutes then cancel of say only allowes to add same message during interval of 1 hour or 1 day
}

What I have tried:

First i would like to check if value already exists or not i have done something like this

Posted 17-Nov-16 22:13pm

Member 11000455

Updated 17-Nov-16 23:14pm

v3

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2 solutions

Solution 1

Just check if key and value exists:

C#

if(hash.ContainsKey("c") && hash["c"] == "3") { }

Posted 17-Nov-16 22:58pm

Er. Puneet Goel

Comments

Member 11000455 18-Nov-16 5:18am

in mycase i have done
if(ht.ContainsKey("Hello") && ht["Hello"] == LoggedOn.ToString())
{
//Do something here
}
but it is always false

Er. Puneet Goel 18-Nov-16 5:21am

Check the solution i added below, that what you need

Member 11000455 18-Nov-16 5:25am

if(hash.ContainsKey("c") && hash["c"] == "3") { } //yoursolution

if(ht.ContainsKey(message) && ht[message] == LoggedOn.ToString()) //same i have done but its same its not working

Member 11000455 18-Nov-16 5:22am

also,

hash.Add("Hello", LoggedOn);
bool htexists = ht.ContainsKey("Hello");
bool valueexists = ht.ContainsValue(LoggedOn);

if (htexists && valueexists)
{
//It returns true which is corred as i have added key and value but i want to check if it is first time or no duplicate value how to checkt it
}

Er. Puneet Goel 18-Nov-16 5:23am

if (hashtable.ContainsKey("Hello") && Convert.ToDateTime((hashtable["Hello"])) != Convert.ToDateTime(LoggedOn))
{
// Add value
}

Er. Puneet Goel 18-Nov-16 5:27am

I have explained that in solution 2. I don't understand what's the issue in that. Try to run that.

Member 11000455 18-Nov-16 5:35am

thanks

Member 11000455 18-Nov-16 5:34am

it works finally but one more ? at the very begining

ht.Add("Hello", LoggedOn);

before this line i want to check if it is first entry or if there is no duplicate value how to do this because my problem is when i use Containskey it retur always true but i want to check if its first entry then allow
if (hashtable.ContainsKey("Hello") && Convert.ToDateTime((hashtable["Hello"])) == Convert.ToDateTime(LoggedOn))
{
//DO Anything
}

Er. Puneet Goel 18-Nov-16 5:37am

please accept this as solution for further assistance as this will help others as well.

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Er. Puneet Goel · Accepted Answer · 2016-11-17T23:14:00

You can also create extension method like below:

C#

public partial class Page2 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        Hashtable hashtable = new Hashtable();
        hashtable.AddIfNotExists("Time1", Convert.ToDateTime("11/18/2016 3:43:33 PM"));
        hashtable.AddIfNotExists("Time2", Convert.ToDateTime("11/18/2016 3:43:34 PM"));
        hashtable.AddIfNotExists("Time3", Convert.ToDateTime("11/18/2016 3:43:33 PM"));
        hashtable.AddIfNotExists("Time4", Convert.ToDateTime("11/18/2016 3:43:35 PM"));   
    }
}

public static class Extension
{
    public static void AddIfNotExists(this Hashtable hash, string key1, DateTime value2)
    {
        if (hash.ContainsKey(key1) == false && Convert.ToDateTime((hash[key1])) != value2)
        {            
            hash.Add(key1, value2);
        }
    }
}