ProductDetails.cs

/**************************************************************************

* @author : Chandar

* @version 1.0

* Development Environment : Microsoft Visual Studio .Net

* Name of the File : ProductDetails.cs

* Creation/Modification History :

12-Oct-2002 Created

* Overview:

* This class defines the methods to retrieve and update details of a

* particular product to database. It also shows how Safe Type Mapping feature

* of ODP.NET can be used to prevent precision loss while retrieving high

* precision data from database.

*****************************************************************************/

using System;

using System.Drawing;

using System.Collections;

using System.ComponentModel;

using System.Windows.Forms;

using System.Data;

using Oracle.DataAccess.Client;

namespace SafeTypeMapping

{

/// <summary>

/// Definition of ProductDetails class.

/// </summary>

public class ProductDetails : System.Windows.Forms.Form

{

// variable to communicate with database

OracleDataAdapter productsAdapter;

// variable to get data from the database

DataSet detailsDataSet;

// variable to store product ID of the product whose details are sought

int productID;

// variable to store the user selection in Products screen

bool safeType;

//definition of various controls on the form

private System.Windows.Forms.Button cmdUpdate;

private System.Windows.Forms.Button cmdClose;

private System.Windows.Forms.Label lblPrice;

private System.Windows.Forms.TextBox txtPrice;

private System.Windows.Forms.Label lblProduct;

private System.Windows.Forms.Label lblName;

private System.Windows.Forms.TextBox txtWeight;

private System.Windows.Forms.Label lblWeight;

private System.Windows.Forms.Label lblPID;

private System.Windows.Forms.Label lblID;

/// <summary>

/// Required designer variable.

/// </summary>

private System.ComponentModel.Container components = null;

public ProductDetails()

{

InitializeComponent();

}

/**********************************************************************

* This method retrieves the details of products from database in

* a DataSet variable using OracleDataAdapter. It uses Safe Type

* Mapping for "Weight" and "Price" column to avoid precision loss while

* retrieving it from database. When Safe Type Mapping is used the

* column data is retrieved as String type rather than default

* .NET types.

* If Safe Type Mapping is not used, the method throws an

* "Arithmetic operation resulted in an overflow" exception

* when precision of column data is higher than that can be handled

* by defalut .NET types.

**********************************************************************/

public bool getProductDetails(int productID, bool safeType)

{

this.productID =productID;

this.safeType=safeType;

try

{

//Instantiate OracleDataAdapter to communicate with database

productsAdapter = new OracleDataAdapter();

// variable to automatically generate commands for making changes

// through DataSet

OracleCommandBuilder productsCmdBuilder = new OracleCommandBuilder(productsAdapter);

//Set the select command to fetch product details

productsAdapter.SelectCommand = new OracleCommand("SELECT " +

"Product_ID,Product_Name,Weight , Price FROM "+

" products WHERE product_id="+productID,

ConnectionManager.conn);

//AddWithKey sets the Primary Key information to complete the

//schema information

productsAdapter.MissingSchemaAction = MissingSchemaAction.AddWithKey;

if(safeType)

{

//Add Safe Mapping for Weight column so that it is retrieved

//as String type instead of default .NET type to avoid precision loss

productsAdapter.SafeMapping.Add("WEIGHT",typeof(string));

//Add Safe Mapping for Price column so that it is retrieved

//as String type instead of default .NET type to avoid prcision loss

productsAdapter.SafeMapping.Add("PRICE",typeof(string));

}

//Instantiate DataSet object

detailsDataSet = new DataSet("DetailsDataSet");

//Fill the DataSet with data from 'Products' database table

productsAdapter.Fill(detailsDataSet, "Products");

// Get the row containing details of product

DataRow row =detailsDataSet.Tables["Products"].Rows[0];

// display the product details on form controls

lblID.Text =row["Product_ID"].ToString();

lblName.Text = row["Product_Name"].ToString();

txtWeight.Text = row["Weight"].ToString();

txtPrice.Text = row["Price"].ToString();

}

catch(Exception ex)

{

//Display error message

MessageBox.Show(ex.Message);

return false;

}

return true;

}

/*****************************************************************

* This method updates the details of products into the database.

* The DataSet object is first edited to incorporate the changes

* to product details and then this DataSet is used to update the

* database table. Safe Type Mapping is used for "Weight" and

* "Price" column to avoid precision loss while updating the values

* into database.

*****************************************************************/

private void updateProductDetails()

{

try

{

//get the Row to be updated

DataRow detailsRow =detailsDataSet.Tables[0].Rows.Find(productID);

// check if user has made any changes to data values

if(txtWeight.Text.Equals(detailsRow["Weight"].ToString())

&& txtPrice.Text.Equals(detailsRow["Price"].ToString()))

{

MessageBox.Show("No changes made");

return;

}

//Start the edit operation on the current row

detailsRow.BeginEdit();

//Assigning the value of product weight

detailsRow["Weight"] = txtWeight.Text;

//Assigning the value of product price

detailsRow["Price"] = txtPrice.Text;

//End the editing current row operation

detailsRow.EndEdit();

// update the changes in DataSet to database

productsAdapter.Update(detailsDataSet,"Products");

// message on successful updation.

MessageBox.Show("Update Successful");

}

catch(Exception e)

{

//Display error message

System.Windows.Forms.MessageBox.Show(e.Message);

}

/*************************************************************

* This event is fired when "Update" button is clicked

* It calls method to update changes to database.

* ***********************************************************/

private void cmdUpdate_Click(object sender, System.EventArgs e)

{

// check if input data is valid

bool proceed =validateInput();

if(proceed)

{

// update details to database

updateProductDetails();

// get the udpated details

getProductDetails(productID,safeType);

}

/***************************************************************

* This method validates the user input before updating it to

* database

**************************************************************/

private bool validateInput()

{

//if weight of product is not entered

if(txtWeight.Text=="")

{

MessageBox.Show("Enter Product Weight");

return false;

}

// check if product weight is valid number

else if(txtWeight.Text!="")

{

try

{

//Parse the string to unsigned integer

double temp =System.Double.Parse(txtWeight.Text);

if(temp<=0)

{

MessageBox.Show("Weight cannot be zero or negative");

return false;

}

catch(Exception ne)

{

txtWeight.Text="";

MessageBox.Show("Enter valid Product Weight");

return false;

}

//if price of product is not entered

if(txtPrice.Text=="")

{

MessageBox.Show("Enter Product Price");

return false;

}

// check if product price is valid number

else if(txtPrice.Text!="")

{

try

{

//Parse the string to unsigned integer

double temp =System.Double.Parse(txtPrice.Text);

if(temp<=0)

{

MessageBox.Show("Price cannot be zero or negative");

return false;

}

catch(Exception ne)

{

txtPrice.Text="";

MessageBox.Show("Enter valid Product Price");

return false;

}

return true;

}

/*************************************************************

* This event is fired when "Close" button is clicked

* It closes the current form.

* ***********************************************************/

private void cmdClose_Click(object sender, System.EventArgs e)

{

this.Close();

}

#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.lblProduct = new System.Windows.Forms.Label();

this.lblWeight = new System.Windows.Forms.Label();

this.lblPrice = new System.Windows.Forms.Label();

this.txtPrice = new System.Windows.Forms.TextBox();

this.cmdUpdate = new System.Windows.Forms.Button();

this.cmdClose = new System.Windows.Forms.Button();

this.lblName = new System.Windows.Forms.Label();

this.txtWeight = new System.Windows.Forms.TextBox();

this.lblPID = new System.Windows.Forms.Label();

this.lblID = new System.Windows.Forms.Label();

this.SuspendLayout();

// lblProduct

this.lblProduct.Font = new System.Drawing.Font("Tahoma", 9.75F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));

this.lblProduct.Location = new System.Drawing.Point(32, 56);

this.lblProduct.Name = "lblProduct";

this.lblProduct.Size = new System.Drawing.Size(104, 24);

this.lblProduct.TabIndex = 0;

this.lblProduct.Text = "Product Name";

// lblWeight

this.lblWeight.Font = new System.Drawing.Font("Tahoma", 9.75F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));

this.lblWeight.Location = new System.Drawing.Point(32, 112);

this.lblWeight.Name = "lblWeight";

this.lblWeight.Size = new System.Drawing.Size(80, 32);

this.lblWeight.TabIndex = 2;

this.lblWeight.Text = "Weight (g)";

// lblPrice

this.lblPrice.Font = new System.Drawing.Font("Tahoma", 9.75F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));

this.lblPrice.Location = new System.Drawing.Point(32, 160);

this.lblPrice.Name = "lblPrice";

this.lblPrice.Size = new System.Drawing.Size(64, 24);

this.lblPrice.TabIndex = 4;

this.lblPrice.Text = "Price ($)";

// txtPrice

this.txtPrice.Font = new System.Drawing.Font("Tahoma", 9.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));

this.txtPrice.Location = new System.Drawing.Point(136, 152);

this.txtPrice.MaxLength = 15;

this.txtPrice.Name = "txtPrice";

this.txtPrice.Size = new System.Drawing.Size(160, 23);

this.txtPrice.TabIndex = 5;

this.txtPrice.Text = "Price";

// cmdUpdate

this.cmdUpdate.Font = new System.Drawing.Font("Tahoma", 9.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));

this.cmdUpdate.Location = new System.Drawing.Point(136, 208);

this.cmdUpdate.Name = "cmdUpdate";

this.cmdUpdate.Size = new System.Drawing.Size(72, 24);

this.cmdUpdate.TabIndex = 6;

this.cmdUpdate.Text = "Update";

this.cmdUpdate.Click += new System.EventHandler(this.cmdUpdate_Click);

// cmdClose

this.cmdClose.Font = new System.Drawing.Font("Tahoma", 9.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));

this.cmdClose.Location = new System.Drawing.Point(216, 208);

this.cmdClose.Name = "cmdClose";

this.cmdClose.Size = new System.Drawing.Size(80, 24);

this.cmdClose.TabIndex = 7;

this.cmdClose.Text = "Close";

this.cmdClose.Click += new System.EventHandler(this.cmdClose_Click);

// lblName

this.lblName.Font = new System.Drawing.Font("Tahoma", 9.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));

this.lblName.Location = new System.Drawing.Point(144, 56);

this.lblName.Name = "lblName";

this.lblName.Size = new System.Drawing.Size(216, 24);

this.lblName.TabIndex = 8;

this.lblName.Text = "Product Name";

// txtWeight

this.txtWeight.Font = new System.Drawing.Font("Tahoma", 9.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));

this.txtWeight.Location = new System.Drawing.Point(136, 104);

this.txtWeight.MaxLength = 38;

this.txtWeight.Name = "txtWeight";

this.txtWeight.Size = new System.Drawing.Size(160, 23);

this.txtWeight.TabIndex = 9;

this.txtWeight.Text = "Weight";

// lblPID

this.lblPID.Font = new System.Drawing.Font("Tahoma", 9.75F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));

this.lblPID.Location = new System.Drawing.Point(32, 16);

this.lblPID.Name = "lblPID";

this.lblPID.TabIndex = 10;

this.lblPID.Text = "Product ID";

// lblID

this.lblID.Font = new System.Drawing.Font("Tahoma", 9.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));

this.lblID.Location = new System.Drawing.Point(144, 16);

this.lblID.Name = "lblID";

this.lblID.Size = new System.Drawing.Size(120, 24);

this.lblID.TabIndex = 11;

this.lblID.Text = "Product ID";

// ProductDetails

this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);

this.ClientSize = new System.Drawing.Size(336, 253);

this.Controls.AddRange(new System.Windows.Forms.Control[] {

this.lblID,

this.lblPID,

this.txtWeight,

this.lblName,

this.cmdClose,

this.cmdUpdate,

this.txtPrice,

this.lblPrice,

this.lblWeight,

this.lblProduct});

this.Name = "ProductDetails";

this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;

this.Text = "Product Details";

this.ResumeLayout(false);

}

#endregion

/// <summary>

/// Clean up any resources being used.

/// </summary>

protected override void Dispose( bool disposing )

{

if( disposing )

{

if (components != null)

{

components.Dispose();

}

base.Dispose( disposing );

}