Microsoft Dynamics CRM (Archived)

How do you test a date field for null value in a plug-in using c#

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Posted on by Community Member

I am trying to test a date field to see if its null or has no value but no luck.

The field is blank on the form.

If I use == null it fails.

When I get the value of the blank date field it returns 1/1/0001 12:00a etc.

I test against the return value as follows:

datefield.ToShortDateString() == "1/1/0001";

it always returns true regardless of the value of the datefield.

I am trying to use the QueryByAttribute method but can't figure out the syntax, I haven't seen any date related examples.

Any help or suggestions would be greatly appreciated.

Thanks

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Mahadeo Matre 17,021 on at

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you can check for minimum date

if(datefield != DateTime.MinValue)

{

//write your code.

}

DateTime.MinValue = 1/1/0001 12:00a

please check

msdn.microsoft.com/.../system.datetime.minvalue(v=vs.110).aspx

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Community Member on at

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Hi Mahadeo,

Thank you for the reply.

After thorough testing,

Results: Did not work

I tried this:

pre-condition:

datefield value: 09/20/2016

Condition:

if (datefield == DateTime.MinValue); // update only if null

or

if (datefield.Equals(DateTime.MinValue) ) // as suggested by the article

in both cases the datefield got updated even if it had some value other than MinValue

Any other suggestions?

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a33ik 84,331 Most Valuable Professional on at

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Actually you don't need to compare that field with any kind of values. When field is updated with null inside plugin you can use following check assuming that target is your entity you got from context:

var entity = context.InputParameters["Target"] as Entity;

if (entity.Contains("new_fieldnamehere") && entity["new_fieldnamehere"] == null)

{

//put your logic of handling null values here

}

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Community Member on at

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If you are using late bound then you need to check in Entity contains key, like:

if(entity.Contais("datefield") && entity.GetAttributeValue<Datetime?>("datefield")!=null){

}

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Community Member on at

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Hi Guido,

Here is the test result:

before:

DateField value: null

code:

DateTime? DateField = entity.GetAttributeValue<DateTime?>("new_datefield");

if (DateField == null)

entity["new_datefield"] = new DateTime(2017,3,1);

result: Fail - datefield value changed to 1/3/2017

Thank You,

next step: going to try other suggestions as well

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Community Member on at

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Hello Andrii,

Thank you for your reply.

Here is the test below:

// throw new InvalidPluginExecutionException("DateDead: " +entity.GetAttributeValue<DateTime>("new_datedead")); // returns 1/1/0001 12:00:00a

Entity entity = (Entity)context.InputParameters["Target"];

if (entity.Contains("new_datedead")){

entity["new_datedead"] = DateTime.Now; // does not get executed

}

results: Fail - does not get passed the if statement

also tried:

if (entity.Attributes.ContainsKey ("new_datedead")) // did not pass either

The weird part is I can read and update but cannot find the attribute

Thanks

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a33ik 84,331 Most Valuable Professional on at

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Field will be available in Target only if you update this attribute on the form. If you haven't touched that field but you want to get its value you can access it through Images.

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Community Member on at

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Ok that makes sense.

Which image should I be looking at Pre or Post update?

thank You

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Community Member on at

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I tried both Pre and Post update images as follows:

// Entity entity = context.PreEntityImages["PreImage"];

Entity entity = context.PostEntityImages["PostImage"];

Returned Business Process Error: "The given key was not present in the dictionary"

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