實作RadioButtonList自定義WinForm控件

目的:項目有需要，建立一個支援資料綁定的單選按鈕清單。

設想：動态識别多種資料源， 動态生成一定數量的按鈕。

準備：建立一個自定義控件，添加一個Panel對象。

優點: 支援多種資料源做綁定，并可以自己添加自定義資料源。

缺點：錯誤的抛出沒有做到位，沒有完全做到設計時定義所有資料。原因：懶。

using  System;

using  System.Collections.Generic;

using  System.ComponentModel;

using  System.Drawing;

using  System.Data;

using  System.Text;

using  System.Windows.Forms;

using  System.Collections;

namespace  RVProject

{

    public partial class RadioButtonList : UserControl

{

        Variable#region Variable

        private Object _dataSource;

        private ButtonValueMapping[] _mappings;

        private Object _internalDataSource;

        private string _displayMember;

        private string _valueMember;

        private string _value;

        #endregion

        ctor.#region ctor.

        public RadioButtonList()

{

            InitializeComponent();

        }

        #endregion

        prop#region prop

        public System.Object DataSource

{

            get

{

                return _dataSource;

            }

            set

{

                _dataSource = value;

            }

        }

        public string DisplayMember

{

            get

{

                return _displayMember;

            }

            set

{

                _displayMember = value;

            }

        }

        public string ValueMember

{

            get

{

                return _valueMember;

            }

            set 

{

                _valueMember = value;

            }

        }

        public string Value

{

            get

{

                return _value;

            }

            set

{

                if (Value != null)

{

                    _value = value;

                    SetValue(value);

                }

            }

        }

        #endregion

        event#region event

        public delegate void RadioSelectedHandler(object sender, SelectedEventArgs e);

        public event RadioSelectedHandler RadioItemSeleted;

        #endregion

        public method#region public method

        public void DataBind()

{

            if (_dataSource == null)

                throw new NullReferenceException("Null reference in Property: DataSource ");

            PrepareData();

            DrawControl();

        }

        #endregion

        //Internal Function

        internal function#region internal function

        void DrawControl()

{

            panel.Controls.Clear();

            int count = _mappings.Length;

            //Draw and set control

            int height = 0;

            int x_aris = 10;

            int y_aris = 10;

            for (int i = 0; i < count; i++)

{

                //create the radio button

                RadioButton radio = new RadioButton();

                radio.Name = i.ToString();

                radio.Text = _mappings[i].Text;

                radio.AutoSize = true;

                //put radio button into the panel

                panel.Controls.Add(radio);

                radio.Location = new Point(x_aris, y_aris + height);

                height += radio.Height;

                //Add click event to radio button

                radio.Click += new EventHandler(radio_Click);

            }

        }

        //Deal with the data source. Add additional code here if you want some new type of objet to be the datasource.

        void PrepareData()

{

            //deal with the datasouce

            if (_dataSource is DataTable)

                _internalDataSource = ((DataTable)_dataSource).DefaultView;

            if (_dataSource is DataView)

                _internalDataSource = _dataSource;

            //Exception

            if (_internalDataSource == null) throw new InvalidCastException("The data source is not a desinged type.");

            //prepare the _radiobutton & _mappings to creat the radio listre

            DataView & DataTable as data source#region DataView & DataTable as data source

            if (_internalDataSource is DataView)

{

                int radioCount = ((DataView)_internalDataSource).Count;

                _mappings = new ButtonValueMapping[radioCount];

                try

{

                    for (int i = 0; i < radioCount; i++)

{

                        //Set index

                        _mappings[i].Index = i;

                        //Set display text

                        _mappings[i].Text = ((DataView)_internalDataSource)[i][_displayMember].ToString();

                        //Set value

                        if (_valueMember == null || _valueMember == string.Empty)

{

                            _mappings[i].Value = i.ToString();

                        }

                        else

{

                            _mappings[i].Value = ((DataView)_internalDataSource)[i][_valueMember].ToString();

                        }

                    }

                }

                catch (Exception e)

{

                    throw e;

                }

            }

            #endregion

        }

        //internal event when a radio button is clicked. this fuction will call a public event.

        void radio_Click(object sender, EventArgs e)

{

            _value = _mappings[int.Parse(((RadioButton)sender).Name)].Value;

            SelectedEventArgs se = new SelectedEventArgs();

            se.Value = _mappings[int.Parse(((RadioButton)sender).Name)].Value;

            RadioItemSeleted(this, se);

        }

        //When Value changes , the relative radio button is selected.

        void SetValue(string value)

{

            if (_mappings == null)

                throw new NullReferenceException("Data has not bound to the control");

            foreach(ButtonValueMapping map in _mappings)

{

                if (map.Value == value)

{

                    ((RadioButton)panel.Controls[map.Index.ToString()]).Checked = true;

                }

            }

        }

        #endregion

        internal struct ButtonValueMapping

{

            public int Index;

            public string Value;

            public string Text;

        }

        public class SelectedEventArgs : EventArgs

{

            public string Value;

        }

    }

}

轉載于:https://www.cnblogs.com/deltag1984/archive/2008/06/06/1215368.html