ASPxGridView.RowDeleting Event

Enables you to prevent a row from being deleted.

Namespace: DevExpress.Web

Assembly: DevExpress.Web.v23.1.dll

NuGet Package: DevExpress.Web

Declaration

C#

public event ASPxDataDeletingEventHandler RowDeleting

VB.NET

Public Event RowDeleting As ASPxDataDeletingEventHandler

Event Data

The RowDeleting event's data class is ASPxDataDeletingEventArgs. The following properties provide information specific to this event:

Property	Description
Cancel	Gets or sets a value indicating whether the event should be canceled. Inherited from CancelEventArgs.
Keys	Gets a dictionary of field name/value pairs that represent the primary key of the row to delete.
Values	Gets a dictionary of the non-key field name/value pairs for the row to delete.

Remarks

The RowDeleting event occurs when an end-user has clicked the Delete command or the ASPxGridView.DeleteRow method has been called. To cancel the delete operation, set the event parameter’s Cancel property to true.

After a row has been deleted, the ASPxGridView.RowDeleted event is raised.

Example

This demo shows how to edit data from an in-memory dataset using the ASPxGridView. To do this, you should:

• handle the RowUpdating, RowInserting, and RowDeleting) events and update the data source manually (the e.NewValues dictionary contains the input value);
• set the e.Cancel parameter to true and call the ASPxGridView.CancelEdit method.

View Example

Default.aspx

<dxwgv:ASPxGridView ID="ASPxGridView1" runat="server" AutoGenerateColumns="False"
    KeyFieldName="ID" OnRowUpdating="ASPxGridView1_RowUpdating" Width="588px" OnRowDeleting="ASPxGridView1_RowDeleting" OnRowInserting="ASPxGridView1_RowInserting">
    <Columns>
        <dxwgv:GridViewCommandColumn VisibleIndex="0" ShowEditButton="True" ShowDeleteButton="True" ShowNewButton="True"/>
        <dxwgv:GridViewDataTextColumn FieldName="ID" ReadOnly="True" VisibleIndex="1">
        </dxwgv:GridViewDataTextColumn>
        <dxwgv:GridViewDataTextColumn FieldName="Data" VisibleIndex="2">
        </dxwgv:GridViewDataTextColumn>
    </Columns>
    <SettingsDetail ShowDetailRow="True" />
    <Templates>
        <DetailRow>
            <dxwgv:ASPxGridView ID="ASPxGridView2" runat="server" AutoGenerateColumns="False"
                KeyFieldName="ID" OnBeforePerformDataSelect="ASPxGridView2_BeforePerformDataSelect"
                OnRowUpdating="ASPxGridView1_RowUpdating" Width="100%">
                <Columns>
                    <dxwgv:GridViewCommandColumn VisibleIndex="0" ShowEditButton="True"/>
                    <dxwgv:GridViewDataTextColumn FieldName="ID" ReadOnly="True" VisibleIndex="1">
                    </dxwgv:GridViewDataTextColumn>
                    <dxwgv:GridViewDataTextColumn FieldName="MasterID" ReadOnly="True" VisibleIndex="2">
                    </dxwgv:GridViewDataTextColumn>
                    <dxwgv:GridViewDataTextColumn FieldName="Data" VisibleIndex="3">
                    </dxwgv:GridViewDataTextColumn>
                </Columns>
            </dxwgv:ASPxGridView>
        </DetailRow>
    </Templates>
</dxwgv:ASPxGridView>

Default.aspx.cs

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using DevExpress.Web;
using System.Collections;

public partial class _Default : System.Web.UI.Page 
{
    DataSet ds = null;
    protected void Page_Init(object sender, EventArgs e) {
        if (!IsPostBack || (Session["DataSet"] == null)) {
            ds = new DataSet();
            DataTable masterTable = new DataTable();
            masterTable.Columns.Add("ID", typeof(int));
            masterTable.Columns.Add("Data", typeof(string));
            masterTable.PrimaryKey = new DataColumn[] { masterTable.Columns["ID"] };

            DataTable detailTable = new DataTable();
            detailTable.Columns.Add("ID", typeof(int));
            detailTable.Columns.Add("MasterID", typeof(int));
            detailTable.Columns.Add("Data", typeof(string));
            detailTable.PrimaryKey = new DataColumn[] { detailTable.Columns["ID"] };
            int index = 0;
            for(int i = 0;i < 20;i++) {
                masterTable.Rows.Add(new object[] { i, "Master Row " + i });
                for(int j = 0;j < 5;j++)
                    detailTable.Rows.Add(new object[] { index++, i, "Detail Row " + j });
            }
            ds.Tables.AddRange(new DataTable[] { masterTable, detailTable });
            Session["DataSet"] = ds;
        }
        else
            ds = (DataSet)Session["DataSet"];
        ASPxGridView1.DataSource = ds.Tables[0];
        ASPxGridView1.DataBind();
    }
    protected void ASPxGridView2_BeforePerformDataSelect(object sender, EventArgs e) {
        ds = (DataSet)Session["DataSet"];
        DataTable detailTable = ds.Tables[1];
        DataView dv = new DataView(detailTable);
        ASPxGridView detailGridView = (ASPxGridView)sender;
        dv.RowFilter = "MasterID = " + detailGridView.GetMasterRowKeyValue();
        detailGridView.DataSource = dv;
    }
    protected void ASPxGridView1_RowUpdating(object sender, DevExpress.Web.Data.ASPxDataUpdatingEventArgs e) {
        ds = (DataSet)Session["DataSet"];
        ASPxGridView gridView = (ASPxGridView)sender;
        DataTable dataTable = gridView.GetMasterRowKeyValue() != null ? ds.Tables[1] : ds.Tables[0];
        DataRow row = dataTable.Rows.Find(e.Keys[0]);
        IDictionaryEnumerator enumerator = e.NewValues.GetEnumerator();
        enumerator.Reset();
        while(enumerator.MoveNext())
            row[enumerator.Key.ToString()] = enumerator.Value;
        gridView.CancelEdit();
        e.Cancel = true;
    }
    protected void ASPxGridView1_RowInserting(object sender, DevExpress.Web.Data.ASPxDataInsertingEventArgs e) {
        ds = (DataSet)Session["DataSet"];
        ASPxGridView gridView = (ASPxGridView)sender;
        DataTable dataTable = gridView.GetMasterRowKeyValue() != null ? ds.Tables[1] : ds.Tables[0];
        DataRow row = dataTable.NewRow();
        e.NewValues["ID"] = GetNewId();
        IDictionaryEnumerator enumerator = e.NewValues.GetEnumerator();
        enumerator.Reset();
        while(enumerator.MoveNext())
            if(enumerator.Key.ToString() != "Count")
                row[enumerator.Key.ToString()] = enumerator.Value;
        gridView.CancelEdit();
        e.Cancel = true;
        dataTable.Rows.Add(row);
    }

    protected void ASPxGridView1_RowDeleting(object sender, DevExpress.Web.Data.ASPxDataDeletingEventArgs e) {
        int i = ASPxGridView1.FindVisibleIndexByKeyValue(e.Keys[ASPxGridView1.KeyFieldName]);
        Control c = ASPxGridView1.FindDetailRowTemplateControl(i, "ASPxGridView2");
        e.Cancel = true;
        ds = (DataSet)Session["DataSet"];
        ds.Tables[0].Rows.Remove(ds.Tables[0].Rows.Find(e.Keys[ASPxGridView1.KeyFieldName]));

    }
    private int GetNewId() {
        ds = (DataSet)Session["DataSet"];
        DataTable table= ds.Tables[0];
        if (table.Rows.Count == 0) return 0;
        int max = Convert.ToInt32(table.Rows[0]["ID"]);
        for (int i = 1; i < table.Rows.Count; i++) {
            if (Convert.ToInt32(table.Rows[i]["ID"]) > max)
                max = Convert.ToInt32(table.Rows[i]["ID"]);
        }
        return max + 1;
    }
}

Default.aspx.vb

Imports System
Imports System.Data
Imports System.Configuration
Imports System.Web
Imports System.Web.Security
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts
Imports System.Web.UI.HtmlControls
Imports DevExpress.Web
Imports System.Collections

Partial Public Class _Default
    Inherits System.Web.UI.Page

    Private ds As DataSet = Nothing
    Protected Sub Page_Init(ByVal sender As Object, ByVal e As EventArgs)
        If (Not IsPostBack) OrElse (Session("DataSet") Is Nothing) Then
            ds = New DataSet()
            Dim masterTable As New DataTable()
            masterTable.Columns.Add("ID", GetType(Integer))
            masterTable.Columns.Add("Data", GetType(String))
            masterTable.PrimaryKey = New DataColumn() { masterTable.Columns("ID") }

            Dim detailTable As New DataTable()
            detailTable.Columns.Add("ID", GetType(Integer))
            detailTable.Columns.Add("MasterID", GetType(Integer))
            detailTable.Columns.Add("Data", GetType(String))
            detailTable.PrimaryKey = New DataColumn() { detailTable.Columns("ID") }
            Dim index As Integer = 0
            For i As Integer = 0 To 19
                masterTable.Rows.Add(New Object() { i, "Master Row " & i })
                For j As Integer = 0 To 4
                    detailTable.Rows.Add(New Object() {index, i, "Detail Row " & j})
                    index += 1
                Next j
            Next i
            ds.Tables.AddRange(New DataTable() { masterTable, detailTable })
            Session("DataSet") = ds
        Else
            ds = DirectCast(Session("DataSet"), DataSet)
        End If
        ASPxGridView1.DataSource = ds.Tables(0)
        ASPxGridView1.DataBind()
    End Sub
    Protected Sub ASPxGridView2_BeforePerformDataSelect(ByVal sender As Object, ByVal e As EventArgs)
        ds = DirectCast(Session("DataSet"), DataSet)
        Dim detailTable As DataTable = ds.Tables(1)
        Dim dv As New DataView(detailTable)
        Dim detailGridView As ASPxGridView = DirectCast(sender, ASPxGridView)
        dv.RowFilter = "MasterID = " & detailGridView.GetMasterRowKeyValue()
        detailGridView.DataSource = dv
    End Sub
    Protected Sub ASPxGridView1_RowUpdating(ByVal sender As Object, ByVal e As DevExpress.Web.Data.ASPxDataUpdatingEventArgs)
        ds = DirectCast(Session("DataSet"), DataSet)
        Dim gridView As ASPxGridView = DirectCast(sender, ASPxGridView)
        Dim dataTable As DataTable = If(gridView.GetMasterRowKeyValue() IsNot Nothing, ds.Tables(1), ds.Tables(0))
        Dim row As DataRow = dataTable.Rows.Find(e.Keys(0))
        Dim enumerator As IDictionaryEnumerator = e.NewValues.GetEnumerator()
        enumerator.Reset()
        Do While enumerator.MoveNext()
            row(enumerator.Key.ToString()) = enumerator.Value
        Loop
        gridView.CancelEdit()
        e.Cancel = True
    End Sub
    Protected Sub ASPxGridView1_RowInserting(ByVal sender As Object, ByVal e As DevExpress.Web.Data.ASPxDataInsertingEventArgs)
        ds = DirectCast(Session("DataSet"), DataSet)
        Dim gridView As ASPxGridView = DirectCast(sender, ASPxGridView)
        Dim dataTable As DataTable = If(gridView.GetMasterRowKeyValue() IsNot Nothing, ds.Tables(1), ds.Tables(0))
        Dim row As DataRow = dataTable.NewRow()
        e.NewValues("ID") = GetNewId()
        Dim enumerator As IDictionaryEnumerator = e.NewValues.GetEnumerator()
        enumerator.Reset()
        Do While enumerator.MoveNext()
            If enumerator.Key.ToString() <> "Count" Then
                row(enumerator.Key.ToString()) = enumerator.Value
            End If
        Loop
        gridView.CancelEdit()
        e.Cancel = True
        dataTable.Rows.Add(row)
    End Sub

    Protected Sub ASPxGridView1_RowDeleting(ByVal sender As Object, ByVal e As DevExpress.Web.Data.ASPxDataDeletingEventArgs)
        Dim i As Integer = ASPxGridView1.FindVisibleIndexByKeyValue(e.Keys(ASPxGridView1.KeyFieldName))
        Dim c As Control = ASPxGridView1.FindDetailRowTemplateControl(i, "ASPxGridView2")
        e.Cancel = True
        ds = DirectCast(Session("DataSet"), DataSet)
        ds.Tables(0).Rows.Remove(ds.Tables(0).Rows.Find(e.Keys(ASPxGridView1.KeyFieldName)))

    End Sub
    Private Function GetNewId() As Integer
        ds = DirectCast(Session("DataSet"), DataSet)
        Dim table As DataTable= ds.Tables(0)
        If table.Rows.Count = 0 Then
            Return 0
        End If
        Dim max As Integer = Convert.ToInt32(table.Rows(0)("ID"))
        For i As Integer = 1 To table.Rows.Count - 1
            If Convert.ToInt32(table.Rows(i)("ID")) > max Then
                max = Convert.ToInt32(table.Rows(i)("ID"))
            End If
        Next i
        Return max + 1
    End Function
End Class