QueryParameter(String, Type, Object) Constructor

Initializes a new instance of the QueryParameter class with specified settings.

Namespace: DevExpress.DataAccess.MongoDB

Assembly: DevExpress.DataAccess.v24.2.dll

Declaration

C#

public QueryParameter(
    string name,
    Type type,
    object value
)

VB.NET

Public Sub New(
    name As String,
    type As Type,
    value As Object
)

Parameters

Name	Type	Description
name	String	The parameter name.
type	Type	The parameter type.
value	Object	The parameter default value.

Example

The example below demonstrates how to use the MongoDBDataSource class to bind an application or component to a MongoDB instance. The example uses the MongoDBCustomConnectionParameters class to specify a connection string to the MongoDB instance and the MongoDBQuery class to specify data queries to the Categories and Products collections of the Northwind database.

C#

using DevExpress.DataAccess.ConnectionParameters;
using DevExpress.DataAccess.MongoDB;
// ...
// Create a MongoDBCustomConnectionParameters object and assign
// a MongoDB connection string to the object's ConnectionString
// property.
var connectionParameters = new MongoDBCustomConnectionParameters() {
    ConnectionString = "mongodb://localhost:27017"
};

// Specify queries to database collections.
var queryParamLowPrice = new QueryParameter() {
    Name = "LowPrice",
    Type = typeof(int),
    Value = 10
};

var queryLowPriceProducts = new MongoDBQuery() {
    DatabaseName = "Northwind",
    CollectionName = "Products",
    Alias = "LowPriceProducts",
    FilterString = "[UnitPrice] <= ?LowPrice",
    Parameters = { queryParamLowPrice }
};

var queryParamHighPrice = new QueryParameter() {
    Name = "HighPrice",
    Type = typeof(int),
    Value = 40
};

var queryHighPriceProducts = new MongoDBQuery() {
    DatabaseName = "Northwind",
    CollectionName = "Products",
    Alias = "HighPriceProducts",
    FilterString = "[UnitPrice] >= ?HighPrice",
    Parameters = { queryParamHighPrice }
};

// Create a MongoDBDataSource object. Assign the created connection
// string to the object's ConnectionParameters property. Add the
// queries to the object's Queries collection.
var mongoDBDataSource = new MongoDBDataSource() {
    ConnectionParameters = connectionParameters,
    Queries = { queryLowPriceProducts, queryHighPriceProducts }
};

// Call the Fill method of the MongoDBDataSource object to execute the
// queries and load data from the MongoDB instance.
mongoDBDataSource.Fill();

// Use the created object as a data source in your application or component.
//...

VB.NET

Imports DevExpress.DataAccess.ConnectionParameters
Imports DevExpress.DataAccess.MongoDB
' ...
' Create a MongoDBCustomConnectionParameters object and assign
' a MongoDB connection string to the object's ConnectionString
' property.
Dim connectionParameters = New MongoDBCustomConnectionParameters() With {
    .ConnectionString = "mongodb://localhost:27017"
}

' Specify queries to database collections.
Dim queryParamLowPrice = New QueryParameter() With {
    .Name = "LowPrice",
    .Type = GetType(Integer),
    .Value = 10
}

Dim queryLowPriceProducts = New MongoDBQuery() With {
    .DatabaseName = "Northwind",
    .CollectionName = "Products",
    .Alias = "LowPriceProducts",
    .FilterString = "[UnitPrice] <= ?LowPrice"
}

queryLowPriceProducts.Parameters.Add(queryParamLowPrice)

Dim queryParamHighPrice = New QueryParameter() With {
    .Name = "HighPrice",
    .Type = GetType(Integer),
    .Value = 40
}

Dim queryHighPriceProducts = New MongoDBQuery() With {
    .DatabaseName = "Northwind",
    .CollectionName = "Products",
    .Alias = "HighPriceProducts",
    .FilterString = "[UnitPrice] >= ?HighPrice"
}

queryHighPriceProducts.Parameters.Add(queryParamHighPrice)

' Create a MongoDBDataSource object. Assign the created connection
' string to the object's ConnectionParameters property. Add the
' queries to the object's Queries collection.
Dim mongoDBDataSource = New MongoDBDataSource() With {
    .ConnectionParameters = connectionParameters
}

mongoDBDataSource.Queries.Add(queryLowPriceProducts)
mongoDBDataSource.Queries.Add(queryHighPriceProducts)

' Call the Fill method of the MongoDBDataSource object to execute the
' queries and load data from the MongoDB instance.
mongoDBDataSource.Fill()

' Use the created object as a data source in your application or component.
'...