Get lookup value from other entity and set it on the form using Web API in Microsoft Dynamics CRM

In this blog i am going to show you , how you can retrieve a lookup value from other entity in CRM using web api and set it on the form.

let see how its done here:

function yourFunctionName() {

var lookup= Xrm.Page.getAttribute(“fieldname”).getValue();  //you will get the id with exxtra double quotes or square brackets by doing get value hence you to make it readable by CRM , you must slice it. i have use the below method:
var newid = lookup[0].id.slice(1, -1);  // you will get perfect id like “EDCJDKDJDKJDJDKJDJKD” here.

var req = new XMLHttpRequest();

once you have the id , you have frame to make a webapi GET call by proving the newid we got.

req.open(“GET”, Xrm.Page.context.getClientUrl() + “/api/data/v8.1/entitypluralname(” + newid + “)?$select=_prefix_fieldname_value”, true);
req.setRequestHeader(“OData-MaxVersion”, “4.0”);
req.setRequestHeader(“OData-Version”, “4.0”);
req.setRequestHeader(“Accept”, “application/json”);
req.setRequestHeader(“Content-Type”, “application/json; charset=utf-8”);
req.setRequestHeader(“Prefer”, “odata.include-annotations=\”*\””);
req.onreadystatechange = function () {
if (this.readyState === 4) {
req.onreadystatechange = null;
if (this.status === 200) {
var result = JSON.parse(this.response); // you will get the retrieved value in object we stored in result var.

var retrivedvalue= result._prefix_fieldname_value; //get the id of the field
var retrivedformatedvalue= result[“_prefix_fieldname_value@OData.Community.Display.V1.FormattedValue”]; //get the formatted name of the field
if (retrivedvalue!= null) {
var value = new Array();
value[0] = new Object();
value[0].id = retrivedvalue;
value[0].name = retrivedformatedvalue;
value[0].entityType = “entityname”;

Xrm.Page.getAttribute(“fieldname”).setValue(value); //set the lookup value finally
}
else
alert(“some textt!!!!!!”) // optional
} else {
Xrm.Utility.alertDialog(this.statusText);
}
}
};
req.send();

}

you can call this function on change of the field.

i hope this helps!!  

cheers!