November 2010 - Taswar Bhatti

Operator ‘==’ cannot be applied to operands of type ‘System.Collections.Generic.KeyValuePair‘ and ‘‘

Taswar Bhatti November 29, 2010 No Comments

You are here beacause you probably got a Linq error, specifically Operator ‘==’ cannot be applied to operands of type ‘System.Collections.Generic.KeyValuePair‘ and ‘‘
So if you wish to do something like this to KeyValuePair using Linq

var item = myDictionary.FirstOrDefault(x => x.Key == 123);
if(item != null)
{
 //blah blah

}

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var item = myDictionary.FirstOrDefault(x => x.Key == 123);

if(item != null)

{

//blah blah

}

You will get this error
Operator ‘!=’ cannot be applied to operands of type ‘System.Collections.Generic.KeyValuePair‘ and ‘‘

Since by default KeyValuePairs are struct.
To solve the issue we need to try out this

 var defaultVal = default(KeyValuePair<int, string>);
var item = myDictionary.FirstOrDefault(x => x.Key == 123);
if(!item.Equals(defaultValue)
{
 //blah blah
}

… Read the rest

.NET, Misc

C#, generics, programming

ASP MVC, Jquery modifying a select drop down with Json data

Taswar Bhatti November 18, 2010 2 Comments

Was coding some new functionality and though I would post this, so that others can find it helpful.
Lets say you have a form that has a checkbox that will update the select dropdown box with different values, when the checkbox is clicked.
Something like the UI below.

Your html code might look like

<input type="hidden" name="fieldId" value="123" />
Parent: <select name="FieldType" id="fieldTypeDropDown">
                        <option value="16">None</option>
                        <option value="4">Apple</option>
                        <option value="3">Orange</option>
                    </select>

Multiple: <input type="checkbox" name="fieldMultiple" id="fieldMultiple" />

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Parent: <select name="FieldType" id="fieldTypeDropDown">

<option value="4">Apple</option>

<option value="3">Orange</option>

</select>

Multiple: <input type="checkbox" name="fieldMultiple"

… Read the rest

aspmvc, JQuery

asp .net mvc, asp mvc, Javascript, JQuery, mvc

Back from Holidays

Taswar Bhatti November 2, 2010 No Comments

So haven’t posted for a while, was in home city Hong Kong for holidays and busy with work releasing software, gonna be posting a few more things coming up this month so be tuned in 🙂

Misc

Operator ‘==’ cannot be applied to operands of type ‘System.Collections.Generic.KeyValuePair‘ and ‘‘

ASP MVC, Jquery modifying a select drop down with Json data

Back from Holidays

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