Friday, 23 January 2009

Making a Field Read-Only via the ReadOnlyAttribute – Dynamic Data

This article is as a result of this thread not editable attribute on the Dynamic Data Forum:

What you need to do is:

  1. Use the ReadOnlyAttribute in System.ComponentModel and attribute up the column you want as read only in edit mode

  2. Create an class that implements IAutoFieldGenrator.

  3. A custom DynamicField.

And here's the sample:

using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Web.DynamicData;
using System.Web.UI;
using System.Web.UI.WebControls;

public class FieldsManager : IAutoFieldGenerator
    protected MetaTable _table;

    public FieldsManager(MetaTable table)
        _table = table;

    public ICollection GenerateFields(Control control)
        var oFields = new List<DynamicField>();

        foreach (var column in _table.Columns)
            // carry on the loop at the next column  
            // if scaffold table is set to false or DenyRead
            if (!column.Scaffold || column.IsLongString)

            DynamicField f;

            // here we check to dee
            if (column.Attributes.OfType<ReadOnlyAttribute>().
DefaultIfEmpty(new ReadOnlyAttribute(false)).
FirstOrDefault().IsReadOnly) f = new DynamicReadonlyField(); else f = new DynamicField(); f.DataField = column.Name; oFields.Add(f); } return oFields; } } // special thanks to david Ebbo for this public class DynamicReadonlyField : DynamicField { public override void InitializeCell( DataControlFieldCell cell, DataControlCellType cellType, DataControlRowState rowState, int rowIndex) { if (cellType == DataControlCellType.DataCell) { var control = new DynamicControl() { DataField = DataField }; // Copy various properties into the control control.UIHint = UIHint; control.HtmlEncode = HtmlEncode; control.NullDisplayText = NullDisplayText; // this the default for DynamicControl and has to be // manually changed you do not need this line of code // its there just to remind us what we are doing. control.Mode = DataBoundControlMode.ReadOnly; cell.Controls.Add(control); } else { base.InitializeCell(cell, cellType, rowState, rowIndex); } } }

And in the Edit page add:

protected void Page_Init(object sender, EventArgs e)
    table = DetailsDataSource.GetTable();
    DetailsView1.RowsGenerator = new FieldsManager(table);

In the Page_Init add the BOLD ITALIC lines

This is a direct copy of the answer I gave in the thread HappyWizard


sksmum said...

i was getting error
var oFields = new List();

changed to (it worked )
List< DynamicField > oFields = new List< DynamicField >();

from post

Steve said...

It may be that the <DynamicField> got dropper if I copied it from the Forum :(

Thanks I'll check the code and update the article

Steve :D