DevExtreme Angular - ODataContext Properties

This section describes the ODataContext's configuration properties.

beforeSend

Specifies a function that customizes the request before it is sent to the server.

Type:

Function

Function parameters:
options:

Object

The request parameters.

Object structure:
Name Type Description
async

Boolean

Indicates whether the request is asynchronous or synchronous.
headers

Object

The request headers.
method

String

The request method ("GET", "POST", "PATCH", or "MERGE").
params

Object

Additional parameters.
payload

Object

The request body; for example, when updating an item, this property holds an object with new values.
Unavailable if the request method is "GET".
timeout

Number

The request timeout.
url

String

The request URL.

jQuery
JavaScript
var context = new DevExpress.data.ODataContext({
    url: "https://js.devexpress.com/Demos/DevAV/odata/",
    entities: { 
        Employees: { 
            key: "Employee_ID", 
            keyType: "Int32" 
        },
        Customers: { 
            key: "Customer_ID", 
            keyType: "Int32" 
        }
    },
    beforeSend: function (e) {  
        e.params = {
            "param1": "value1",
            "param2": "value2"
        };
        e.headers = {
            "Custom Header": "value"
        };
    }
});
Angular
TypeScript
import ODataContext from "devextreme/data/odata/context";
// ...
export class AppComponent {
    context: ODataContext;
    constructor() {
        this.context = new ODataContext({
            url: "https://js.devexpress.com/Demos/DevAV/odata/",
            entities: { 
                Employees: { 
                    key: "Employee_ID", 
                    keyType: "Int32" 
                },
                Customers: { 
                    key: "Customer_ID", 
                    keyType: "Int32" 
                }
            },
            beforeSend: (e) => {  
                e.params = {
                    "param1": "value1",
                    "param2": "value2"
                };
                e.headers = {
                    "Custom Header": "value"
                };
            }
        });
    }
}
Vue
App.vue
<script>
import ODataContext from 'devextreme/data/odata/context';

const context = new ODataContext({
    url: 'https://js.devexpress.com/Demos/DevAV/odata/',
    entities: { 
        Employees: { 
            key: 'Employee_ID', 
            keyType: 'Int32' 
        },
        Customers: { 
            key: 'Customer_ID', 
            keyType: 'Int32' 
        }
    },
    beforeSend: (e) => {  
        e.params = {
            'param1': 'value1',
            'param2': 'value2'
        };
        e.headers = {
            'Custom Header': 'value'
        };
    }
});

export default {
    // ...
}
</script>
React
App.js
// ...
import ODataContext from 'devextreme/data/odata/context';

const context = new ODataContext({
    url: 'https://js.devexpress.com/Demos/DevAV/odata/',
    entities: { 
        Employees: { 
            key: 'Employee_ID', 
            keyType: 'Int32' 
        },
        Customers: { 
            key: 'Customer_ID', 
            keyType: 'Int32' 
        }
    },
    beforeSend: (e) => {  
        e.params = {
            'param1': 'value1',
            'param2': 'value2'
        };
        e.headers = {
            'Custom Header': 'value'
        };
    }
});

class App extends React.Component {
    // ...
}
export default App;

deserializeDates

Specifies whether stores in the ODataContext serialize/parse date-time values.

Type:

Boolean

Stores can parse date-time values in ISO8601 format (for example, "2016-07-13T16:05:00.000Z") or Microsoft format (for instance, "/Date(1198908717056)/"). In the first case, the store ignores the timezone modifier (usually Z) when parsing the value. In the second case, the store adds the time-zone offset to the value according to the client's time-zone.

NOTE

Disabling deserialization may cause filtering issues in UI components bound to the ODataStore. When deserialization is disabled in the store, date-time strings are converted to Date objects at the UI component level. When filtering, the UI component reverts an entered date-time value to a string based on the dateSerializationFormat property's value and passes the string to the ODataStore for further processing. Because OData does not support strings, filtering fails.

To prevent these issues, the store's deserializeDates property should be set to true or set the UI component's dateSerializationFormat property to null.

entities

Specifies entity collections to be accessed.

Type: any

The ODataContext creates an ODataStore per entity collection, so you need to use ODataStore properties for configuring access to entity collections. In the following code, access to the Employees and Customers entity collections is configured, but only Customers is loaded using the load() method:

jQuery
JavaScript
var context = new DevExpress.data.ODataContext({
    url: "https://js.devexpress.com/Demos/DevAV/odata/",
    entities: { 
        // Configures access to "https://js.devexpress.com/Demos/DevAV/odata/Employees"
        Employees: { 
            key: "Employee_ID", 
            keyType: "Int32" 
        },
        // Configures access to "https://js.devexpress.com/Demos/DevAV/odata/Customers"
        Clients: {              // The collection alias
            name: "Customers",  // The collection name
            key: "Customer_ID", 
            keyType: "Int32" 
        }
    }
});
context.Clients.load();
Angular
TypeScript
import ODataContext from "devextreme/data/odata/context";
// ...
export class AppComponent {
    context: ODataContext;
    constructor() {
        this.context = new ODataContext({
            url: "https://js.devexpress.com/Demos/DevAV/odata/",
            entities: { 
                // Configures access to "https://js.devexpress.com/Demos/DevAV/odata/Employees"
                Employees: { 
                    key: "Employee_ID", 
                    keyType: "Int32" 
                },
                // Configures access to "https://js.devexpress.com/Demos/DevAV/odata/Customers"
                Clients: {              // The collection alias
                    name: "Customers",  // The collection name
                    key: "Customer_ID", 
                    keyType: "Int32" 
                }
            }
        });
        this.context.Clients.load();
    }
}
Vue
App.vue
<script>
import ODataContext from 'devextreme/data/odata/context';

const context = new ODataContext({
    url: 'https://js.devexpress.com/Demos/DevAV/odata/',
    entities: { 
        // Configures access to "https://js.devexpress.com/Demos/DevAV/odata/Employees"
        Employees: { 
            key: 'Employee_ID', 
            keyType: 'Int32' 
        },
        // Configures access to "https://js.devexpress.com/Demos/DevAV/odata/Customers"
        Clients: {              // The collection alias
            name: 'Customers',  // The collection name
            key: 'Customer_ID', 
            keyType: 'Int32' 
        }
    }
});

export default {
    mounted: {
        context.Clients.load();
    },
    // ...
}
</script>
React
App.js
// ...
import ODataContext from 'devextreme/data/odata/context';

const context = new ODataContext({
    url: 'https://js.devexpress.com/Demos/DevAV/odata/',
    entities: { 
        // Configures access to "https://js.devexpress.com/Demos/DevAV/odata/Employees"
        Employees: { 
            key: 'Employee_ID', 
            keyType: 'Int32' 
        },
        // Configures access to "https://js.devexpress.com/Demos/DevAV/odata/Customers"
        Clients: {              // The collection alias
            name: 'Customers',  // The collection name
            key: 'Customer_ID', 
            keyType: 'Int32' 
        }
    }
});

class App extends React.Component {
    constructor(props) {
        super(props);
        context.Clients.load();
    }
}
export default App;

errorHandler

Specifies a function that is executed when the ODataContext throws an error.

Type:

Function

Function parameters:
e:

JavaScript Error Object

|

Object

A JavaScript Error object extended with the following fields:

Object structure:
Name Type Description
errorDetails

Object

Error details. It is an OData error response object for OData-specific errors or a jqXHR object for other errors when you use jQuery.
httpStatus

Number

The error code.
requestOptions

Object

Request details. Contains the following fields:

  • accepts: Object
    The data types that the client accepts mapped to their MIME types.

  • async: Boolean
    Indicates whether the request was asynchronous or synchronous.

  • contentType: String | Boolean
    The content type; false if no content type was specified.

  • data: Object
    Query options.

  • dataType: String
    The expected data type.

  • headers: Object
    The request headers.

  • jsonp: Boolean
    Indicates whether the request was sent using JSONP.

  • method: String
    The request method ("GET", "POST", "PATCH", or "MERGE").

  • timeout: Number
    The request timeout.

  • url: String
    The request URL.

  • xhrFields: Object
    Native XMLHttpRequest object properties that were sent in the request.

jQuery
JavaScript
var context = new DevExpress.data.ODataContext({
    // ...
    errorHandler: function(error) {
        console.log(error.message);
    }
});
Angular
TypeScript
import ODataContext from "devextreme/data/odata/context";
// ...
export class AppComponent {
    context: ODataContext;
    constructor() {
        this.context = new ODataContext({
            // ...
            errorHandler: (error) => {
                console.log(error.message);
            }
        })
    }
}
Vue
App.vue
<script>
import ODataContext from 'devextreme/data/odata/context';

const context = new ODataContext({
    // ...
    errorHandler: (error) => {
        console.log(error.message);
    }
});

export default {
    // ...
}
</script>
React
App.js
// ...
import ODataContext from 'devextreme/data/odata/context';

const context = new ODataContext({
    // ...
    errorHandler: (error) => {
        console.log(error.message);
    }
});

class App extends React.Component {
    // ...
}
export default App;

filterToLower

Specifies whether to convert string values to lowercase in filter and search requests. Applies to the following operations: "startswith", "endswith", "contains", and "notcontains".

Type:

Boolean

Defaults to the global oDataFilterToLower setting.

When this property is true, the filter expression sent to the server contains a tolower() function call and a lowercase filter value.

jQuery
JavaScript
var context = new DevExpress.data.ODataContext({
    url: "https://js.devexpress.com/Demos/DevAV/odata/",
    entities: { 
        Employees: { 
            key: "Employee_ID", 
            keyType: "Int32" 
        }, // ...
    },
    filterToLower: true
});
var ds = new DevExpress.data.DataSource({
    store: context.Employees,
    filter: ["Employee_Name", "startswith", "Jo"]
});

// The filter expression in the request looks like the following:
// https://...?filter=startswith(tolower(Employee_Name), 'jo')
Angular
app.component.ts
import ODataContext from 'devextreme/data/odata/context';
import DataSource from 'devextreme/data/data_source';
// ...
export class AppComponent {
    context: ODataContext;
    ds: DataSource;
    constructor() {
        this.context = new ODataContext({
            url: "https://js.devexpress.com/Demos/DevAV/odata/",
            entities: { 
                Employees: { 
                    key: "Employee_ID", 
                    keyType: "Int32" 
                }, // ...
            },
            filterToLower: true
        });
        this.ds = new DataSource({
            store: this.context.Employees,
            filter: ["Employee_Name", "startswith", "Jo"]
        });

        // The filter expression in the request looks like the following:
        // https://...?filter=startswith(tolower(Employee_Name), 'jo')
    }
}
Vue
App.vue
<script>
import ODataContext from 'devextreme/data/odata/context';
import DataSource from 'devextreme/data/data_source';

const context = new ODataContext({
    url: 'https://js.devexpress.com/Demos/DevAV/odata/',
    entities: { 
        Employees: { 
            key: 'Employee_ID', 
            keyType: 'Int32' 
        },
        // ...
    },
    filterToLower: true
});

const ds = new DataSource({
    store: context.Employees,
    filter: ['Employee_Name', 'startswith', 'Jo']
});

// The filter expression in the request looks like the following:
// https://...?filter=startswith(tolower(Employee_Name), 'jo')

export default {
    // ...
}
</script>
React
App.js
// ...
import ODataContext from 'devextreme/data/odata/context';
import DataSource from 'devextreme/data/data_source';

const context = new ODataContext({
    url: 'https://js.devexpress.com/Demos/DevAV/odata/',
    entities: { 
        Employees: { 
            key: 'Employee_ID', 
            keyType: 'Int32' 
        },
        // ...
    },
    filterToLower: true
});

const ds = new DataSource({
    store: context.Employees,
    filter: ['Employee_Name', 'startswith', 'Jo']
});

// The filter expression in the request looks like the following:
// https://...?filter=startswith(tolower(Employee_Name), 'jo')

class App extends React.Component {
    // ...
}
export default App;

jsonp

Specifies whether data should be sent using JSONP.

Type:

Boolean

Default Value: false

url

Specifies the URL of an OData service.

Type:

String

jQuery
JavaScript
var context = new DevExpress.data.ODataContext({
    // ...
    url: "https://js.devexpress.com/Demos/DevAV/odata/"
});
Angular
TypeScript
import ODataContext from "devextreme/data/odata/context";
// ...
export class AppComponent {
    context: ODataContext;
    constructor() {
        this.context = new ODataContext({
            // ...
            url: "https://js.devexpress.com/Demos/DevAV/odata/"
        });
    }
}
Vue
App.vue
<script>
import ODataContext from 'devextreme/data/odata/context';

const context = new ODataContext({
    // ...
    url: 'https://js.devexpress.com/Demos/DevAV/odata/'
});

export default {
    // ...
}
</script>
React
App.js
// ...
import ODataContext from 'devextreme/data/odata/context';

const context = new ODataContext({
    // ...
    url: 'https://js.devexpress.com/Demos/DevAV/odata/'
});

class App extends React.Component {
    // ...
}
export default App;
See Also

version

Specifies the OData version.

Type:

Number

Default Value: 2
Accepted Values: 2 | 3 | 4

If the version is 2, the ODataContext uses the "MERGE" method to send requests; otherwise, it uses "PATCH". Set the method field of the beforeSend function's parameter to override this behavior.

withCredentials

Specifies whether to send cookies, authorization headers, and client certificates in a cross-origin request.

Type:

Boolean

Default Value: false

This property's value is passed to the underlying jqXHR object.

Use the beforeSend function to specify custom authorization headers.