RowToFieldTransformer.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / xsp / System / Web / UI / WebParts / RowToFieldTransformer.cs / 1305376 / 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.Web.UI.WebControls;

    [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); 
            }
        } 
    }
}


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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RowToFieldTransformer.cs source code in C# .NET

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