RowToFieldTransformer.cs source code in C# .NET

                        Code:
                         / FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / fx / src / xsp / System / Web / UI / WebParts / RowToFieldTransformer.cs / 1 / RowToFieldTransformer.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Web.UI.WebControls.WebParts { 
 
    using System;
    using System.ComponentModel; 
    using System.Diagnostics;
    using System.Security.Permissions;
    using System.Web.UI.WebControls;
 
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    [WebPartTransformer(typeof(IWebPartRow), typeof(IWebPartField))] 
    public sealed class RowToFieldTransformer : WebPartTransformer, IWebPartField { 

        private IWebPartRow _provider; 
        private string _fieldName;

        // We know there is only 1 RowCallback, since transformers can only have 1 consumer
        private FieldCallback _callback; 

        public override Control CreateConfigurationControl() { 
            return new RowToFieldConfigurationWizard(this); 
        }
 
        public string FieldName {
            get {
                return (_fieldName != null) ? _fieldName : String.Empty;
            } 
            set {
                _fieldName = value; 
            } 
        }
 
        private PropertyDescriptorCollection ProviderSchema {
            get {
                return (_provider != null) ? _provider.Schema : null;
            } 
        }
 
        private void GetRowData(object rowData) { 
            Debug.Assert(_callback != null);
 
            object fieldValue = null;

            if (rowData != null) {
                PropertyDescriptor prop = ((IWebPartField)this).Schema; 
                if (prop != null) {
                    fieldValue = prop.GetValue(rowData); 
                } 
            }
 
            _callback(fieldValue);
        }

        protected internal override void LoadConfigurationState(object savedState) { 
            _fieldName = (string)savedState;
        } 
 
        protected internal override object SaveConfigurationState() {
            return _fieldName; 
        }

        public override object Transform(object providerData) {
            _provider = (IWebPartRow)providerData; 
            return this;
        } 
 
        #region Implementation of IWebPartField
        void IWebPartField.GetFieldValue(FieldCallback callback) { 
            if (callback == null) {
                throw new ArgumentNullException("callback");
            }
 
            if (_provider != null) {
                _callback = callback; 
                _provider.GetRowData(new RowCallback(GetRowData)); 
            }
            else { 
                callback(null);
            }
        }
 
        PropertyDescriptor IWebPartField.Schema {
            get { 
                PropertyDescriptorCollection schema = ProviderSchema; 
                return (schema != null) ? schema.Find(FieldName, /* ignoreCase */ true) : null;
            } 
        }
        #endregion

        private sealed class RowToFieldConfigurationWizard : TransformerConfigurationWizardBase { 
            private DropDownList _fieldName;
            private RowToFieldTransformer _owner; 
 
            private const string fieldNameID = "FieldName";
 
            public RowToFieldConfigurationWizard(RowToFieldTransformer owner) {
                Debug.Assert(owner != null);
                _owner = owner;
            } 

            // Dummy consumer schema 
            protected override PropertyDescriptorCollection ConsumerSchema { 
                get {
                    return null; 
                }
            }

            protected override PropertyDescriptorCollection ProviderSchema { 
                get {
                    return _owner.ProviderSchema; 
                } 
            }
 
            protected override void CreateWizardSteps() {
                // The WizardSteps should be empty when this is called
                Debug.Assert(WizardSteps.Count == 0);
 
                WizardStep s = new WizardStep();
 
                _fieldName = new DropDownList(); 
                _fieldName.ID = fieldNameID;
                if (OldProviderNames != null) { 
                    for (int i=0; i < OldProviderNames.Length / 2; i++) {
                        ListItem item = new ListItem(OldProviderNames[2*i], OldProviderNames[2*i + 1]);
                        // Ignore case when setting selected value, since we ignore case when
                        // returing the connection data. (VSWhidbey 434566) 
                        if (String.Equals(item.Value, _owner.FieldName, StringComparison.OrdinalIgnoreCase)) {
                            item.Selected = true; 
                        } 
                        _fieldName.Items.Add(item);
                    } 
                }
                else {
                    _fieldName.Items.Add(new ListItem(SR.GetString(SR.RowToFieldTransformer_NoProviderSchema)));
                    _fieldName.Enabled = false; 
                }
 
                Label fieldNameLabel = new Label(); 
                fieldNameLabel.Text = SR.GetString(SR.RowToFieldTransformer_FieldName);
                fieldNameLabel.AssociatedControlID = _fieldName.ID; 

                s.Controls.Add(fieldNameLabel);
                s.Controls.Add(new LiteralControl(" "));
                s.Controls.Add(_fieldName); 

                WizardSteps.Add(s); 
            } 

            protected override void OnFinishButtonClick(WizardNavigationEventArgs e) { 
                Debug.Assert(_fieldName != null);

                string selectedFieldName = null;
                if (_fieldName.Enabled) { 
                    selectedFieldName = _fieldName.SelectedValue;
                } 
                _owner.FieldName = selectedFieldName; 

                base.OnFinishButtonClick(e); 
            }
        }
    }
}
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RowToFieldTransformer.cs source code in C# .NET

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