ADO.NET Binding: Handling Errors
/*
User Interfaces in C#: Windows Forms and Custom Controls
by Matthew MacDonald
Publisher: Apress
ISBN: 1590590457
*/
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
namespace ADO.NET_Binding
{
/// <summary>
/// Summary description for HandlingErrors.
/// </summary>
public class HandlingErrors : System.Windows.Forms.Form
{
internal System.Windows.Forms.Label lblErrorSummary;
internal System.Windows.Forms.Button cmdNext;
internal System.Windows.Forms.Button cmdPrev;
internal System.Windows.Forms.Label Label4;
internal System.Windows.Forms.GroupBox GroupBox1;
internal System.Windows.Forms.Label Label3;
internal System.Windows.Forms.Label Label2;
internal System.Windows.Forms.Label Label1;
internal System.Windows.Forms.TextBox txtModelName;
internal System.Windows.Forms.TextBox txtDescription;
internal System.Windows.Forms.TextBox txtUnitCost;
internal System.Windows.Forms.TextBox txtModelNumber;
internal System.Windows.Forms.ComboBox cboModelName;
/// <summary>
/// Required designer variable.
/// </summary>
private System.ComponentModel.Container components = null;
public HandlingErrors()
{
//
// Required for Windows Form Designer support
//
InitializeComponent();
//
// TODO: Add any constructor code after InitializeComponent call
//
}
/// <summary>
/// Clean up any resources being used.
/// </summary>
protected override void Dispose( bool disposing )
{
if( disposing )
{
if(components != null)
{
components.Dispose();
}
}
base.Dispose( disposing );
}
#region Windows Form Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.lblErrorSummary = new System.Windows.Forms.Label();
this.cmdNext = new System.Windows.Forms.Button();
this.cmdPrev = new System.Windows.Forms.Button();
this.Label4 = new System.Windows.Forms.Label();
this.GroupBox1 = new System.Windows.Forms.GroupBox();
this.Label3 = new System.Windows.Forms.Label();
this.Label2 = new System.Windows.Forms.Label();
this.Label1 = new System.Windows.Forms.Label();
this.txtModelName = new System.Windows.Forms.TextBox();
this.txtDescription = new System.Windows.Forms.TextBox();
this.txtUnitCost = new System.Windows.Forms.TextBox();
this.txtModelNumber = new System.Windows.Forms.TextBox();
this.cboModelName = new System.Windows.Forms.ComboBox();
this.GroupBox1.SuspendLayout();
this.SuspendLayout();
//
// lblErrorSummary
//
this.lblErrorSummary.ForeColor = System.Drawing.Color.Red;
this.lblErrorSummary.Location = new System.Drawing.Point(26, 296);
this.lblErrorSummary.Name = "lblErrorSummary";
this.lblErrorSummary.Size = new System.Drawing.Size(328, 40);
this.lblErrorSummary.TabIndex = 29;
//
// cmdNext
//
this.cmdNext.Anchor = (System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Right);
this.cmdNext.FlatStyle = System.Windows.Forms.FlatStyle.System;
this.cmdNext.Location = new System.Drawing.Point(322, 348);
this.cmdNext.Name = "cmdNext";
this.cmdNext.Size = new System.Drawing.Size(92, 28);
this.cmdNext.TabIndex = 28;
this.cmdNext.Text = "Next >>";
this.cmdNext.Click += new System.EventHandler(this.cmdNext_Click);
//
// cmdPrev
//
this.cmdPrev.Anchor = (System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left);
this.cmdPrev.FlatStyle = System.Windows.Forms.FlatStyle.System;
this.cmdPrev.Location = new System.Drawing.Point(18, 348);
this.cmdPrev.Name = "cmdPrev";
this.cmdPrev.Size = new System.Drawing.Size(92, 28);
this.cmdPrev.TabIndex = 27;
this.cmdPrev.Text = "<< Prev";
this.cmdPrev.Click += new System.EventHandler(this.cmdPrev_Click);
//
// Label4
//
this.Label4.Location = new System.Drawing.Point(14, 16);
this.Label4.Name = "Label4";
this.Label4.Size = new System.Drawing.Size(88, 16);
this.Label4.TabIndex = 26;
this.Label4.Text = "Select a Record:";
//
// GroupBox1
//
this.GroupBox1.Anchor = (((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom)
| System.Windows.Forms.AnchorStyles.Left)
| System.Windows.Forms.AnchorStyles.Right);
this.GroupBox1.Controls.AddRange(new System.Windows.Forms.Control[] {
this.Label3,
this.Label2,
this.Label1,
this.txtModelName,
this.txtDescription,
this.txtUnitCost,
this.txtModelNumber});
this.GroupBox1.FlatStyle = System.Windows.Forms.FlatStyle.System;
this.GroupBox1.Location = new System.Drawing.Point(14, 48);
this.GroupBox1.Name = "GroupBox1";
this.GroupBox1.Size = new System.Drawing.Size(400, 228);
this.GroupBox1.TabIndex = 25;
this.GroupBox1.TabStop = false;
//
// Label3
//
this.Label3.Location = new System.Drawing.Point(220, 56);
this.Label3.Name = "Label3";
this.Label3.Size = new System.Drawing.Size(36, 16);
this.Label3.TabIndex = 18;
this.Label3.Text = "Cost:";
//
// Label2
//
this.Label2.Location = new System.Drawing.Point(16, 56);
this.Label2.Name = "Label2";
this.Label2.Size = new System.Drawing.Size(52, 16);
this.Label2.TabIndex = 17;
this.Label2.Text = "Model:";
//
// Label1
//
this.Label1.Location = new System.Drawing.Point(16, 28);
this.Label1.Name = "Label1";
this.Label1.Size = new System.Drawing.Size(52, 16);
this.Label1.TabIndex = 16;
this.Label1.Text = "Name:";
//
// txtModelName
//
this.txtModelName.Location = new System.Drawing.Point(68, 24);
this.txtModelName.Name = "txtModelName";
this.txtModelName.Size = new System.Drawing.Size(316, 21);
this.txtModelName.TabIndex = 15;
this.txtModelName.Text = "";
//
// txtDescription
//
this.txtDescription.Location = new System.Drawing.Point(12, 92);
this.txtDescription.Multiline = true;
this.txtDescription.Name = "txtDescription";
this.txtDescription.Size = new System.Drawing.Size(372, 116);
this.txtDescription.TabIndex = 14;
this.txtDescription.Text = "";
//
// txtUnitCost
//
this.txtUnitCost.Location = new System.Drawing.Point(256, 52);
this.txtUnitCost.Name = "txtUnitCost";
this.txtUnitCost.Size = new System.Drawing.Size(128, 21);
this.txtUnitCost.TabIndex = 13;
this.txtUnitCost.Text = "";
//
// txtModelNumber
//
this.txtModelNumber.Location = new System.Drawing.Point(68, 52);
this.txtModelNumber.Name = "txtModelNumber";
this.txtModelNumber.Size = new System.Drawing.Size(136, 21);
this.txtModelNumber.TabIndex = 12;
this.txtModelNumber.Text = "";
//
// cboModelName
//
this.cboModelName.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList;
this.cboModelName.Location = new System.Drawing.Point(106, 10);
this.cboModelName.Name = "cboModelName";
this.cboModelName.Size = new System.Drawing.Size(308, 21);
this.cboModelName.TabIndex = 24;
//
// HandlingErrors
//
this.AutoScaleBaseSize = new System.Drawing.Size(5, 14);
this.ClientSize = new System.Drawing.Size(428, 386);
this.Controls.AddRange(new System.Windows.Forms.Control[] {
this.lblErrorSummary,
this.cmdNext,
this.cmdPrev,
this.Label4,
this.GroupBox1,
this.cboModelName});
this.Font = new System.Drawing.Font("Tahoma", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
this.Name = "HandlingErrors";
this.Text = "HandlingErrors";
this.Load += new System.EventHandler(this.HandlingErrors_Load);
this.GroupBox1.ResumeLayout(false);
this.ResumeLayout(false);
}
#endregion
[STAThread]
static void Main()
{
Application.Run(new HandlingErrors());
}
private BindingManagerBase storeBinding;
private int currentPage;
private bool errFlag;
private void HandlingErrors_Load(object sender, System.EventArgs e)
{
DataSet dsStore = new DataSet();
dsStore.ReadXmlSchema(Application.StartupPath + "\\store.xsd");
dsStore.ReadXml(Application.StartupPath + "\\store.xml");
cboModelName.DataSource = dsStore.Tables["Products"];
cboModelName.DisplayMember = "ModelName";
txtModelName.DataBindings.Add("Text", dsStore.Tables["Products"], "ModelName");
txtModelNumber.DataBindings.Add("Text", dsStore.Tables["Products"], "ModelNumber");
txtUnitCost.DataBindings.Add("Text", dsStore.Tables["Products"], "UnitCost");
txtDescription.DataBindings.Add("Text", dsStore.Tables["Products"], "Description");
storeBinding = this.BindingContext[dsStore.Tables["Products"]];
storeBinding.PositionChanged += new EventHandler(Binding_PositionChanged);
dsStore.Tables["Products"].ColumnChanged += new
DataColumnChangeEventHandler(TableChanging);
}
private void Binding_PositionChanged(object sender, System.EventArgs e)
{
if (errFlag)
{
// Reset the page.
storeBinding.Position = currentPage;
}
else
{
// Allow the page to change and update the currentPage variable.
currentPage = storeBinding.Position;
}
}
private void TableChanging(object sender, System.Data.DataColumnChangeEventArgs e)
{
string errors = DBStore.ValidateProduct(e.Row);
if (errors == "")
{
errFlag = false;
}
else
{
errFlag = true;
}
lblErrorSummary.Text = errors;
}
private void cmdNext_Click(object sender, System.EventArgs e)
{
storeBinding.Position++;
}
private void cmdPrev_Click(object sender, System.EventArgs e)
{
storeBinding.Position--;
}
}
public class DBStore
{
public static string ValidateProduct(DataRow row)
{
string errors = "";
if (((decimal)row["UnitCost"]) <= 0)
{
errors += "* UnitCost value too low\n";
}
if (row["ModelNumber"].ToString() == "")
{
errors += "* You must specify a ModelNumber\n";
}
if (row["ModelName"].ToString() == "")
{
errors += "* You must specify a ModelName\n";
}
return errors;
}
}
}
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