Compile this program with the command line:

csc t:/winexe databound.cs

The setup of the objects on the form will be familiar to you so we don’t need to re-iterate those principles. The interesting parts are on lines 91–95 which creates and populates a simple StringCollection. Remember that the .NET collections all implement the IList interface, making them candidates for databinding. Lines 98 and 99 perform the actual binding of the data to the textboxes. Finally, the click handlers on lines 114–119 and 122–127 move forward or backward through the data by moving the position, analogous to the cursor in a database, through the data.

Simple Binding to a DataSet

Binding of all sorts of controls is an important feature of .NET. Databound controls are available in Windows Forms, WebForms, and ASP.NET. All these controls can use ADO.NET to bind to database tables either on the local machine or somewhere else on the network. The vehicle for database binding is the DataSet. This class represents a set of cached data that is held in memory. The data cache can be created manually or populated with data drawn from a database using ADO.NET’s database connection system. After the information is in that memory store on your machine, you can bind controls to individual columns of data and select rows for editing or viewing.

The easiest way to understand a DataSet is to use it. Listing 3.3.2 shows an application that generates and manipulates a simple DataSet on your machine using simple binding to controls.

3.3

OUNDB ATAD

ONTROLSC

Data Bound Controls

CHAPTER 3.3

LISTING 3.3.2 Continued

45:Application.Exit();

46:}

47:

48://Method to move to the last record. Used when adding a row.

49:private void MoveToEnd()

50:{

51:this.BindingContext[dataset.Tables[“Contacts”]].Position=

52:dataset.Tables[“Contacts”].Rows.Count-1;

53:}

54:

55://Method to add a new row to the table. Called at initialization

56://and by the “New” button handler.

57:private void NewEntry()

58:{

59:DataRow row = dataset.Tables[“Contacts”].NewRow();

60://set up row data with new entries of your choice

61:row[“First”]=”Blank”;

62:row[“Name”]=””;

63:row[“Company”]=””;

64:row[“Title”]=””;

65:row[“Phone”]=””;

66:dataset.Tables[0].Rows.Add(row);

67:dataset.AcceptChanges();

68:MoveToEnd();

69:}

70:

71://Called at creation to initialize the

72://dataset and create an empty table

73:private void InitDataSet()

74:{

75:dataset = new DataSet(“ContactData”);

77: DataTable t=new DataTable(“Contacts”); 78:

79:t.Columns.Add(“First”,typeof(System.String));

80:t.Columns.Add(“Name”,typeof(System.String));

81:t.Columns.Add(“Company”,typeof(System.String));

82:t.Columns.Add(“Title”,typeof(System.String));

83:t.Columns.Add(“Phone”,typeof(System.String));

87:dataset.Tables.Add(t);

88:}

285

3.3

OUNDB ATAD

ONTROLSC

Data Bound Controls

CHAPTER 3.3

LISTING 3.3.2 Continued

128:lbl_name.Size = new Size(120,28);

129:lbl_name.Anchor = AnchorStyles.Left|AnchorStyles.Right;

130:Controls.Add(lbl_name);

131:

132:SurName = new TextBox();

133:SurName.Location = new Point(125,35);

134:SurName.Size = new Size(120,28);

135:SurName.Anchor = AnchorStyles.Left | AnchorStyles.Right;

136:Controls.Add(SurName);

137:

138:lbl_company = new Label();

139:lbl_company.Text=”Company”;

140:lbl_company.Location = new Point(5,65);

141:lbl_company.Size = new Size(120,28);

142:Controls.Add(lbl_company);

143:

144:Company = new TextBox();

145:Company.Location = new Point(125,65);

146:Company.Size = new Size(120,28);

147:Controls.Add(Company);

148:

149:lbl_title = new Label();

150:lbl_title.Text=”Title”;

151:lbl_title.Location = new Point(5,95);

152:lbl_title.Size = new Size(120,28);

153:Controls.Add(lbl_title);

154:

155:Title = new TextBox();

156:Title.Location = new Point(125,95);

157:Title.Size = new Size(120,28);

158:Controls.Add(Title);

159:

160:lbl_phone = new Label();

161:lbl_phone.Text=”Telephone”;

162:lbl_phone.Location = new Point(5,125);

163:lbl_phone.Size = new Size(120,28);

164:Controls.Add(lbl_phone);

165:

166:Phone = new TextBox();

167:Phone.Location = new Point(125,125);

168:Phone.Size = new Size(120,28);

169:Controls.Add(Phone);

170:

171: btnNew = new Button();

287

3.3

OUNDB ATAD

ONTROLSC