Hashtable in ASP.net

Posted by .Netlearner under ASP.NET on 12/5/2012 | Points: 10 | Views : 1789 | Status : [Member] | Replies : 5

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Hello All,

Am having a hashtable in which am adding values dynamically,While Inserting i want to find that whether the pair(key with value) already exists . If the pair is not present already i must be able to insert it .

I Googled in net but i got Conditions that checks only whether the key is present already or whether the value is present already.I didnt find condition to check as a pair.Can anyone please guide me.Thanks in advance.

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Posted by: Somu475 on: 12/5/2012 [Member] Starter | Points: 25

0	Hi, As there is no direct method to check for the existence of Key/Value pair, You can use some simple logic as below... Dim myHashTable As New Hashtable myHashTable.Add("Key1", "Value1") myHashTable.Add("Key2", "Value2") Dim key As String = Me.TxtKey.Text Dim value As String = Me.TxtValue.Text If myHashTable.ContainsKey(key) And myHashTable.ContainsValue(value) Then MsgBox("Key/Value pair already exists!") ElseIf myHashTable.ContainsKey(key) Then MsgBox("Key already exists!") ElseIf myHashTable.ContainsValue(value) Then MsgBox("Value already exists!") Else myHashTable.Add(key, value) End If Mark as Answer if it helps you... -Somu .Netlearner, if this helps please login to Mark As Answer. \| Alert Moderator

Hi,

As there is no direct method to check for the existence of Key/Value pair,
You can use some simple logic as below...

Dim myHashTable As New Hashtable



myHashTable.Add("Key1", "Value1")

myHashTable.Add("Key2", "Value2")



Dim key As String = Me.TxtKey.Text

Dim value As String = Me.TxtValue.Text



If myHashTable.ContainsKey(key) And myHashTable.ContainsValue(value) Then

    MsgBox("Key/Value pair already exists!")

ElseIf myHashTable.ContainsKey(key) Then

    MsgBox("Key already exists!")

ElseIf myHashTable.ContainsValue(value) Then

    MsgBox("Value already exists!")

Else

    myHashTable.Add(key, value)

End If

Mark as Answer if it helps you...

-Somu

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Posted by: Pavanandey on: 12/5/2012 [Member] Bronze | Points: 25

0	Hashtable H1 = new Hashtable(); H1.Add("Key1", "Value1"); H1.Add("Key2", "Value2"); if (!H1.ContainsKey("Key3") && !H1.ContainsValue("Value3")) { H1.Add("Key3", "Value3"); } Thanks Pavan Kumar Mark Answer if this fits the need .Netlearner, if this helps please login to Mark As Answer. \| Alert Moderator

Posted by: .Netlearner on: 12/5/2012 [Member] Starter | Points: 25

0	i want to insert as follows 24-->a 24-->b 24-->c 25-->a 25-->d 25-->c while inserting in hashtable the second row it displays the error that the key is already present.I Dont Know whether am wrong but i thought i can insert same keys with different values, and so thought to check whether particular key with particular value (Ex.24-->a) is present or not.If not i want to insert that in hashtable. whether is is possible ? .Netlearner, if this helps please login to Mark As Answer. \| Alert Moderator

i want to insert as follows

24-->a
24-->b
24-->c
25-->a
25-->d
25-->c

while inserting in hashtable the second row it displays the error that the key is already present.I Dont Know whether am wrong but i thought i can insert same keys with different values, and so thought to check whether particular key with particular value (Ex.24-->a) is present or not.If not i want to insert that in hashtable. whether is is possible ?

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Posted by: Somu475 on: 12/5/2012 [Member] Starter | Points: 25

0	I think we can't Insert same keys repeatedly in Hashtable. If you want to Insert multiple Values for the same key, put all those values in a List and then add that List as a Value in Hashtable. List<string> list = new List<string>(); list.Add("a"); list.Add("b"); list.Add("c"); HashTable obj = new HashTable(); obj.Add("24", list); -Somu .Netlearner, if this helps please login to Mark As Answer. \| Alert Moderator

I think we can't Insert same keys repeatedly in Hashtable.

If you want to Insert multiple Values for the same key, put all those values in a List and then add that List as a Value in Hashtable.

List<string> list = new List<string>();

list.Add("a");

list.Add("b");

list.Add("c");  



HashTable obj = new HashTable();

obj.Add("24", list);

-Somu

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Posted by: Sandhyab on: 12/11/2012 [Member] Starter | Points: 25

0	protected void Page_Load(object sender, EventArgs e) { Hashtable hshTable = new Hashtable(); hshTable.Add("FirstName", "S"); hshTable.Add("LastName", "B"); if (!hshTable.ContainsKey("MiddleName") && !hshTable.ContainsValue("P")) { hshTable.Add("MiddleName", "P"); } GetHash(hshTable); } private void GetHash(Hashtable H1) { IDictionaryEnumerator ide = H1.GetEnumerator(); while (ide.MoveNext()) { Response.Write(ide.Key + "" + ide.Value + "<br/>" + "the value can be" + H1[ide.Key].ToString() + "<br/>"); } } .Netlearner, if this helps please login to Mark As Answer. \| Alert Moderator

 protected void Page_Load(object sender, EventArgs e)

    {

        Hashtable hshTable = new Hashtable();



        hshTable.Add("FirstName", "S");

        hshTable.Add("LastName", "B");



        if (!hshTable.ContainsKey("MiddleName") && !hshTable.ContainsValue("P"))

        {

            hshTable.Add("MiddleName", "P");

        }

        GetHash(hshTable);

    



    }



    private void GetHash(Hashtable H1)

    {

        IDictionaryEnumerator ide = H1.GetEnumerator();

        while (ide.MoveNext())

        {

            Response.Write(ide.Key + "" + ide.Value + "<br/>" + "the value can be" + H1[ide.Key].ToString() + "<br/>");

        }

    }

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