Description
The ASP.NET Hashtable is also a collection of items containing a single data value with key. Here, the use of key is the specialty for Hashtable. This key is used as index for searching of value in a very fast way.
Like ArrayList, even here one can use ‘Add()’ method to add items to the table.
[csharp] Hashtable spHashtable = new Hashtable();
spHashtable.Add("1", "Sunday");
spHashtable.Add("2", "Monday");
spHashtable.Add("3", "Tuesday");
spHashtable.Add("4", "Wednesday");
spHashtable.Add("5", "Thursday");
spHashtable.Add("6", "Friday");
spHashtable.Add("7", "Saturday");
[/csharp]
In the above code, one can see that 7 days of a week have been added to the Hashtable using ‘Add()’ method.
Hashtable can also be used as a data source for data binding controls like RadioButtonList, CheckBoxList etc.
Example
In the below example, one can see on clicking a button a CheckBoxList is populated and the data source for this CheckBoxList is a Hashtable.
In designer, one Button control and one CheckBoxList has been added.
In ‘Default.aspx.cs’ page, under ‘spButton_Click’ event the code has been written to add days to the spHashtable using ‘Add()’ method.
[csharp] protected void spButton_Click(object sender, EventArgs e)
{
Hashtable spHashtable = new Hashtable();
spHashtable.Add("1", "Sunday");
spHashtable.Add("2", "Monday");
spHashtable.Add("3", "Tuesday");
spHashtable.Add("4", "Wednesday");
spHashtable.Add("5", "Thursday");
spHashtable.Add("6", "Friday");
spHashtable.Add("7", "Saturday");
spCheckBoxList.DataSource = spHashtable;
spCheckBoxList.DataValueField = "key";
spCheckBoxList.DataTextField = "value";
spCheckBoxList.DataBind();
} [/csharp]
When viewed the aspx in browser, one will get the following screens. At first only the button will appear in the page. On clicking the button a CheckBoxList will be shown with the days.
After clicking the button. below, page will appear.
