LinqDataSource.Update(IDictionary, IDictionary, IDictionary) Method

  • Reference

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.Extensions.dll

Performs an update operation.

public:
 int Update(System::Collections::IDictionary ^ keys, System::Collections::IDictionary ^ values, System::Collections::IDictionary ^ oldValues);
public int Update (System.Collections.IDictionary keys, System.Collections.IDictionary values, System.Collections.IDictionary oldValues);
member this.Update : System.Collections.IDictionary * System.Collections.IDictionary * System.Collections.IDictionary -> int
Public Function Update (keys As IDictionary, values As IDictionary, oldValues As IDictionary) As Integer

Parameters

keys
IDictionary

The row key values for the records to be updated.

values
IDictionary

The row values to be updated in the data source.

oldValues
IDictionary

The row values that are evaluated to detect data conflicts.

Returns

Int32

The number of records affected by the update operation.

Examples

The following example shows how to programmatically update a record in the data source after the user clicks a button. The code passes a ListDictionary object that contains the key value, a ListDictionary object that contains the original values, and a ListDictionary object that contains the new values to the Update method.

protected void Reset_Click(object sender, EventArgs e)
{
    ListDictionary keyValues = new ListDictionary();
    ListDictionary newValues = new ListDictionary();
    ListDictionary oldValues = new ListDictionary();

    keyValues.Add("ProductID", int.Parse(((Label)DetailsView1.FindControl("IDLabel")).Text));

    oldValues.Add("ProductName", ((Label)DetailsView1.FindControl("NameLabel")).Text);
    oldValues.Add("ProductCategory", ((Label)DetailsView1.FindControl("CategoryLabel")).Text);
    oldValues.Add("Color", ((Label)DetailsView1.FindControl("ColorLabel")).Text);

    newValues.Add("ProductName", "New Product");
    newValues.Add("ProductCategory", "General");
    newValues.Add("Color", "Not assigned");

    LinqDataSource1.Update(keyValues, newValues, oldValues);

    DetailsView1.DataBind();
}

Protected Sub Add_Click(ByVal sender As Object, ByVal e As System.EventArgs)
    Dim keyValues As New ListDictionary()
    Dim newValues As New ListDictionary()
    Dim oldValues As New ListDictionary()

    keyValues.Add("ProductID", Int32.Parse(CType(DetailsView1.FindControl("IDLabel"), Label).Text))

    oldValues.Add("ProductName", CType(DetailsView1.FindControl("NameLabel"), Label).Text)
    oldValues.Add("ProductCategory", CType(DetailsView1.FindControl("CategoryLabel"), Label).Text)
    oldValues.Add("Color", CType(DetailsView1.FindControl("ColorLabel"), Label).Text)

    newValues.Add("ProductName", "New Product")
    newValues.Add("ProductCategory", "General")
    newValues.Add("Color", "Not assigned")

    LinqDataSource1.Update(keyValues, newValues, oldValues)

    DetailsView1.DataBind()
End Sub

The following example shows the markup for the previous example.

<asp:LinqDataSource  
  ContextTypeName="ExampleDataContext" 
  TableName="Products" 
  EnableUpdate="true" 
  ID="LinqDataSource1" 
  runat="server">
</asp:LinqDataSource>
<asp:DetailsView 
  DataSourceID="LinqDataSource1" 
  AllowPaging="True" 
  ID="DetailsView1" 
  runat="server" 
  AutoGenerateRows="False">
  <Fields>
    <asp:templatefield HeaderText="Product ID">
        <itemtemplate>
            <asp:Label ID="IDLabel" runat="server" Text='<%# Bind("ProductID") %>'></asp:Label>
        </itemtemplate>
    </asp:templatefield>
    <asp:templatefield HeaderText="Product Name">
        <itemtemplate>
            <asp:Label ID="NameLabel" runat="server" Text='<%# Bind("ProductName") %>'></asp:Label>
        </itemtemplate>
    </asp:templatefield>
    <asp:templatefield HeaderText="Category">
        <itemtemplate>
            <asp:Label ID="CategoryLabel" runat="server" Text='<%# Bind("ProductCategory") %>'></asp:Label>
        </itemtemplate>
    </asp:templatefield>
    <asp:templatefield HeaderText="Color">
        <itemtemplate>
            <asp:Label ID="ColorLabel" runat="server" Text='<%# Bind("Color") %>'></asp:Label>
        </itemtemplate>
    </asp:templatefield>
  </Fields>
</asp:DetailsView>
<asp:button 
  ID="Button1"
  Text="Reset with default values" 
  runat="server" 
  onclick="Reset_Click" />

<asp:LinqDataSource  
  ContextTypeName="ExampleDataContext" 
  TableName="Products" 
  EnableUpdate="true" 
  ID="LinqDataSource1" 
  runat="server">
</asp:LinqDataSource>
<asp:DetailsView 
  DataSourceID="LinqDataSource1" 
  AllowPaging="True" 
  ID="DetailsView1" 
  runat="server" AutoGenerateRows="False">
  <Fields>
  <asp:templatefield HeaderText="Product ID">
        <itemtemplate>
            <asp:Label ID="IDLabel" runat="server" Text='<%# Bind("ProductID") %>'></asp:Label>
        </itemtemplate>
    </asp:templatefield>
    <asp:templatefield HeaderText="Product Name">
        <itemtemplate>
            <asp:Label ID="NameLabel" runat="server" Text='<%# Bind("ProductName") %>'></asp:Label>
        </itemtemplate>
    </asp:templatefield>
    <asp:templatefield HeaderText="Category">
        <itemtemplate>
            <asp:Label ID="CategoryLabel" runat="server" Text='<%# Bind("ProductCategory") %>'></asp:Label>
        </itemtemplate>
    </asp:templatefield>
    <asp:templatefield HeaderText="Color">
        <itemtemplate>
            <asp:Label ID="ColorLabel" runat="server" Text='<%# Bind("Color") %>'></asp:Label>
        </itemtemplate>
    </asp:templatefield>
  </Fields>
</asp:DetailsView>
<asp:button 
  ID="Button1"
  Text="Reset with default values" 
  runat="server" 
  onclick="Add_Click" />

Remarks

Typically, you do not have to call the Update method from your code. The data-bound control will automatically call the Update method when the user takes action to update a record. You explicitly call the Update method when you want to create your own process for updating data.

Applies to