AsymmetricAlgorithm.FromXmlString(String) Method

Definition

Namespace:

System.Security.Cryptography

Assembly:

System.Security.Cryptography.dll

Source:

AsymmetricAlgorithm.cs

When overridden in a derived class, reconstructs an AsymmetricAlgorithm object from an XML string. Otherwise, throws a NotImplementedException.

public:
 virtual void FromXmlString(System::String ^ xmlString);

public virtual void FromXmlString (string xmlString);

abstract member FromXmlString : string -> unit
override this.FromXmlString : string -> unit

Public Overridable Sub FromXmlString (xmlString As String)

Parameters

xmlString

String

The XML string to use to reconstruct the AsymmetricAlgorithm object.

Examples

The following code example demonstrates how to implement the FromXmlString method to parse the specified XML string to populate the current CspParameters object. This code example is part of a larger example provided for the AsymmetricAlgorithm class.

    // Expected XML schema:
    //      <ProviderName></ProviderName>
    //      <KeyContainerName></KeyContainerName>
    //      <KeyNumber></KeyNumber>
    //      <ProviderType></ProviderType>
public:
    virtual void FromXmlString(String^ xmlString) override 
    {
        if (xmlString != nullptr)
        {
            XmlDocument^ document = gcnew XmlDocument();
            document->LoadXml(xmlString);
            XmlNode^ firstNode = document->FirstChild;
            XmlNodeList^ nodeList;

            // Assemble parameters from values in each XML element.
            cryptoServiceParameters = gcnew CspParameters();

            // KeyContainerName is optional.
            nodeList = 
                document->GetElementsByTagName("KeyContainerName");
            if (nodeList->Count > 0)
            {
                cryptoServiceParameters->KeyContainerName =
                    nodeList->Item(0)->InnerText;
            }

            // KeyNumber is optional.
            nodeList = document->GetElementsByTagName("KeyNumber");
            if (nodeList->Count > 0)
            {
                cryptoServiceParameters->KeyNumber =
                    Int32::Parse(nodeList->Item(0)->InnerText);
            }

            // ProviderName is optional.
            nodeList = document->GetElementsByTagName("ProviderName");
            if (nodeList->Count > 0)
            {
                cryptoServiceParameters->ProviderName =
                    nodeList->Item(0)->InnerText;
            }

            // ProviderType is optional.
            nodeList = document->GetElementsByTagName("ProviderType");
            if (nodeList->Count > 0)
            {
                cryptoServiceParameters->ProviderType =
                    Int32::Parse(nodeList->Item(0)->InnerText);
            }
        }
        else
        {
            throw gcnew ArgumentNullException("xmlString");
        }
    }

// Expected XML schema:
//      <ProviderName></ProviderName>
//      <KeyContainerName></KeyContainerName>
//      <KeyNumber></KeyNumber>
//      <ProviderType></ProviderType>
public override void FromXmlString(string xmlString)
{
    if (xmlString != null)
    {
        XmlDocument doc = new XmlDocument();
        doc.LoadXml(xmlString);
        XmlNode firstNode = doc.FirstChild;
        XmlNodeList nodeList;

        // Assemble parameters from values in each XML element.
        cspParameters = new CspParameters();

        // KeyContainerName is optional.
        nodeList = doc.GetElementsByTagName("KeyContainerName");
        string keyName = nodeList.Item(0).InnerText;
        if (keyName != null) 
        {
            cspParameters.KeyContainerName = keyName;
        }

        // KeyNumber is optional.
        nodeList = doc.GetElementsByTagName("KeyNumber");
        string keyNumber = nodeList.Item(0).InnerText;
        if (keyNumber != null) 
        {
            cspParameters.KeyNumber = Int32.Parse(keyNumber);
        }

        // ProviderName is optional.
        nodeList = doc.GetElementsByTagName("ProviderName");
        string providerName = nodeList.Item(0).InnerText;
        if (providerName != null) 
        {
            cspParameters.ProviderName = providerName;
        }

        // ProviderType is optional.
        nodeList = doc.GetElementsByTagName("ProviderType");
        string providerType = nodeList.Item(0).InnerText;
        if (providerType != null) 
        {
            cspParameters.ProviderType = Int32.Parse(providerType);
        }
    }
    else
    {
        throw new ArgumentNullException("xmlString");
    }
}

' Expected XML schema:
'      <ProviderName></ProviderName>
'      <KeyContainerName></KeyContainerName>
'      <KeyNumber></KeyNumber>
'      <ProviderType></ProviderType>
Public Overrides Sub FromXmlString(ByVal xmlString As String)
    If Not xmlString Is Nothing Then
        Dim doc As New XmlDocument
        doc.LoadXml(xmlString)
        Dim firstNode As XmlNode = doc.FirstChild
        Dim nodeList As XmlNodeList

        ' Assemble parameters from values in each XML element.
        cspParameters = New CspParameters

        ' KeyContainerName is optional.
        nodeList = doc.GetElementsByTagName("KeyContainerName")
        Dim keyName As String = nodeList.Item(0).InnerText
        If Not keyName Is Nothing Then
            cspParameters.KeyContainerName = keyName
        End If

        ' KeyNumber is optional.
        nodeList = doc.GetElementsByTagName("KeyNumber")
        Dim keyNumber As String = nodeList.Item(0).InnerText
        If Not keyNumber Is Nothing Then
            cspParameters.KeyNumber = Int32.Parse(keyNumber)
        End If

        ' ProviderName is optional.
        nodeList = doc.GetElementsByTagName("ProviderName")
        Dim providerName As String = nodeList.Item(0).InnerText
        If Not providerName Is Nothing Then
            cspParameters.ProviderName = providerName
        End If

        ' ProviderType is optional.
        nodeList = doc.GetElementsByTagName("ProviderType")
        Dim providerType As String = nodeList.Item(0).InnerText
        If Not providerType Is Nothing Then
            cspParameters.ProviderType = Int32.Parse(providerType)
        End If
    Else
        Throw New ArgumentNullException("xmlString")
    End If
End Sub

See also

• Cryptographic Services