1. Introduction

First, I decided to write this article to share some of intuited knowledge, try to help and demonstrate how it is possible to develop a simple and generic module for validating XML files with their respective schema files.
2. Project Structure
3. XmlAndSchemaValidator Class Library Source Code
  1. using System;
  2. using System.Xml;
  3. using System.Xml.Schema;
  4. using System.IO;
  5. using System.Text;
  7. namespace XmlAndSchemaValidator
  8. {
  9. public class Validator
  10. {
  11. #region Attributes
  12. private System.Xml.XmlTextReader _XmlTextReader = null;
  13. private System.Xml.XmlReader _XmlReader = null;
  14. private System.Xml.XmlReaderSettings _XmlReaderSettings = null;
  15. private System.Xml.XmlParserContext _XmlParserContext = null;
  16. private System.Xml.Schema.XmlSchemaSet _XmlSchemaSet = null;
  17. private string _ValidationError = string.Empty;
  18. #endregion
  20. #region Object Constructor
  21. public Validator()
  22. {
  23. this._XmlSchemaSet = new System.Xml.Schema.XmlSchemaSet();
  24. this._XmlParserContext = new System.Xml.XmlParserContext(null, null, "", XmlSpace.None);
  26. ValidationEventHandler _ValidationEventHandler = new ValidationEventHandler(ValidationErrors);
  27. }
  28. #endregion
  30. #region Validate
  31. // This Method will validate a Xml File
  32. public string Validate(Int32 _EncodingType, FileInfo _XmlFile, XmlNodeType _XmlNodeType, string _Namespace, string _URI)
  33. {
  34. System.Text.UTF8Encoding _UTF8Encoding = new System.Text.UTF8Encoding();
  35. System.Text.UTF32Encoding _UTF32Encoding = new System.Text.UTF32Encoding();
  36. System.Text.Encoding _Encoding = System.Text.Encoding.GetEncoding("ISO-8859-1");
  37. Int32 _StartIndex = 0;
  38. Int32 _EndIndex = 0;
  39. string _XmlString = string.Empty;
  40. Byte[] _Buffer = null;
  41. FileStream _FileStream = null;
  43. try
  44. {
  45. // Verifies if the Xml file exists on the filesystem
  46. if (_XmlFile.Exists)
  47. {
  48. try
  49. {
  50. _FileStream = _XmlFile.OpenRead();
  51. _Buffer = new Byte[_FileStream.Length];
  53. _FileStream.Read(_Buffer, 0, _Buffer.Length);
  55. // Read the Xml file content with a pre-determinated encoding
  56. switch (_EncodingType.ToString())
  57. {
  58. case "1":
  59. _XmlString = _UTF8Encoding.GetString(_Buffer);
  60. break;
  62. case "2":
  63. _XmlString = _UTF32Encoding.GetString(_Buffer);
  64. break;
  66. case "3":
  67. _XmlString = _Encoding.GetString(_Buffer);
  68. break;
  69. }
  71. _XmlString = _XmlString.Replace("\r", "");
  72. _XmlString = _XmlString.Replace("\n", "");
  73. _XmlString = _XmlString.Replace("\t", "");
  75. _FileStream.Close();
  76. }
  77. catch
  78. {
  79. _FileStream.Close();
  80. }
  81. }
  83. // Add the NameSpace and the Schema file for validation
  84. this._XmlSchemaSet.Add(_Namespace, _URI);
  86. // Creates the XmlTextReader based on the Xml file content
  87. this._XmlTextReader = new XmlTextReader(_XmlString, _XmlNodeType, this._XmlParserContext);
  88. this._XmlTextReader.Read();
  90. // Setup XmlReaderSettings
  91. this._XmlReaderSettings = new System.Xml.XmlReaderSettings();
  92. this._XmlReaderSettings.ValidationType = ValidationType.Schema;
  93. this._XmlReaderSettings.IgnoreComments = true;
  94. this._XmlReaderSettings.IgnoreWhitespace = true;
  96. // Add the NameSpace and the Schema file for validation
  97. this._XmlReaderSettings.Schemas.Add(_Namespace, _URI);
  99. // ConformanceLevel Auto indicates that the XML writer should determine the level of conformance
  100. this._XmlReaderSettings.ConformanceLevel = ConformanceLevel.Auto;
  102. // Creates a XmlReader based on the information gathered on XmlTextReader and assumes the XmlReaderSettings
  103. this._XmlReader = System.Xml.XmlReader.Create(this._XmlTextReader, this._XmlReaderSettings);
  105. // This step will read all Xml file and throw an exception when the
  106. // xml file is not valid
  107. while (this._XmlReader.Read())
  108. {
  110. }
  111. }
  112. catch (XmlException _XmlException)
  113. {
  114. this._ValidationError = _XmlException.Message;
  115. }
  116. catch (XmlSchemaException _XmlSchemaException)
  117. {
  118. this._ValidationError = _XmlSchemaException.Message;
  119. }
  120. catch (Exception _Exception)
  121. {
  122. this._ValidationError = _Exception.Message;
  123. }
  125. // Manipulate the error message
  126. if (this._ValidationError.Trim().ToString() != string.Empty)
  127. {
  128. _StartIndex = this._ValidationError.IndexOf("An error occurred at");
  129. _EndIndex = this._ValidationError.Length - (this._ValidationError.Length - _StartIndex);
  131. if (_StartIndex >= 0)
  132. this._ValidationError = this._ValidationError.Substring(0, _EndIndex);
  133. }
  135. return this._ValidationError;
  136. }
  138. // This Method will validate a Xml String
  139. public string Validate(string _XmlString, XmlNodeType _XmlNodeType, string _Namespace, string _URI)
  140. {
  141. Int32 _StartIndex = 0;
  142. Int32 _EndIndex = 0;
  144. try
  145. {
  146. // Add the NameSpace and the Schema file for validation
  147. this._XmlSchemaSet.Add(_Namespace, _URI);
  149. // Creates the XmlTextReader based on the Xml file content
  150. this._XmlTextReader = new XmlTextReader(_XmlString, _XmlNodeType, this._XmlParserContext);
  151. this._XmlTextReader.Read();
  153. // Setup XmlReaderSettings
  154. this._XmlReaderSettings = new System.Xml.XmlReaderSettings();
  155. this._XmlReaderSettings.ValidationType = ValidationType.Schema;
  156. this._XmlReaderSettings.IgnoreComments = true;
  157. this._XmlReaderSettings.IgnoreWhitespace = true;
  159. // Add the NameSpace and the Schema file for validation
  160. this._XmlReaderSettings.Schemas.Add(_Namespace, _URI);
  162. // ConformanceLevel Auto indicates that the XML writer should determine the level of conformance
  163. this._XmlReaderSettings.ConformanceLevel = ConformanceLevel.Auto;
  165. // Creates a XmlReader based on the information gathered on XmlTextReader and assumes the XmlReaderSettings
  166. this._XmlReader = System.Xml.XmlReader.Create(this._XmlTextReader, this._XmlReaderSettings);
  168. // This step will read all Xml file and throw an exception when the
  169. // xml file is not valid
  170. while (this._XmlReader.Read())
  171. {
  173. }
  174. }
  175. catch (XmlException _XmlException)
  176. {
  177. this._ValidationError = _XmlException.Message;
  178. }
  179. catch (XmlSchemaException _XmlSchemaException)
  180. {
  181. this._ValidationError = _XmlSchemaException.Message;
  182. }
  183. catch (Exception _Exception)
  184. {
  185. this._ValidationError = _Exception.Message;
  186. }
  188. // Manipulate the error message
  189. if (this._ValidationError.Trim().ToString() != string.Empty)
  190. {
  191. _StartIndex = this._ValidationError.IndexOf("An error occurred at");
  192. _EndIndex = this._ValidationError.Length-(this._ValidationError.Length-_StartIndex);
  194. this._ValidationError = this._ValidationError.Substring(0,_EndIndex);
  195. }
  197. return this._ValidationError;
  198. }
  199. #endregion
  201. #region Validation Errors
  202. public static void ValidationErrors(object sender, ValidationEventArgs args)
  203. {
  205. }
  206. #endregion
  207. }
  208. }
4. XmlAndSchemaValidator Tester Application Validation Windows Form Source Code
  1. using System;
  2. using System.IO;
  3. using System.Collections.Generic;
  4. using System.ComponentModel;
  5. using System.Data;
  6. using System.Drawing;
  7. using System.Linq;
  8. using System.Text;
  9. using System.Windows.Forms;
  11. namespace XmlAndSchemaValidator.Tester
  12. {
  13. public partial class ValidationForm : Form
  14. {
  15. #region Attibutes
  16. private DialogResult _DialogResult;
  17. private XmlAndSchemaValidator.Validator _Validator = null;
  18. #endregion
  20. #region Object Constructor
  21. public ValidationForm()
  22. {
  23. InitializeComponent();
  24. }
  25. #endregion
  27. #region Events
  28. #region bntSelectXmlFile_Click
  29. private void bntSelectXmlFile_Click(object sender, EventArgs e)
  30. {
  31. string _ErrorMsg = string.Empty;
  33. try
  34. {
  35. this.txtXmlFile.Text = string.Empty;
  37. this.ofdXmlFile = new OpenFileDialog();
  38. this.ofdXmlFile.Filter = "Xml Files (*.xml)|*.xml|All Files (*.*)|*.*";
  39. this.ofdXmlFile.Title = "Select Xml file for Schema validation";
  40. this._DialogResult = this.ofdXmlFile.ShowDialog();
  42. if (this._DialogResult == System.Windows.Forms.DialogResult.OK)
  43. {
  44. if (this.ofdXmlFile.FileName != string.Empty)
  45. {
  46. this.txtXmlFile.Text = this.ofdXmlFile.FileName.ToString().Trim();
  47. }
  48. }
  49. }
  50. catch (Exception _Exception)
  51. {
  52. _ErrorMsg = string.Empty;
  53. _ErrorMsg = "*************** Error ***************" + "\r\n";
  54. _ErrorMsg = _ErrorMsg + " -> Event: bntSelectXmlFile_Click\r\n";
  55. _ErrorMsg = _ErrorMsg + " -> Message: " + _Exception.Message.ToString() + "\r\n";
  56. _ErrorMsg = _ErrorMsg + " -> Stack Trace: " + _Exception.StackTrace.ToString() + "\r\n";
  58. if (_Exception.InnerException != null)
  59. {
  60. _ErrorMsg = _ErrorMsg + " -> InnerException Message: " + _Exception.InnerException.Message.ToString() + "\r\n";
  61. _ErrorMsg = _ErrorMsg + " -> InnerException Stack Trace: " + _Exception.InnerException.StackTrace.ToString() + "\r\n";
  62. }
  64. _ErrorMsg = "*************************************";
  66. MessageBox.Show(_ErrorMsg, "XmlAndSchemaValidator", MessageBoxButtons.OK, MessageBoxIcon.Error);
  67. }
  68. }
  69. #endregion
  71. #region bntSelectXsdFile_Click
  72. private void bntSelectXsdFile_Click(object sender, EventArgs e)
  73. {
  74. string _ErrorMsg = string.Empty;
  76. try
  77. {
  78. this.txtXsdFile.Text = string.Empty;
  80. this.ofdXsdFile = new OpenFileDialog();
  81. this.ofdXsdFile.Filter = "Xsd Files (*.Xsd)|*.Xsd|All Files (*.*)|*.*";
  82. this.ofdXsdFile.Title = "Select Xsd file to use in validation";
  83. this._DialogResult = this.ofdXsdFile.ShowDialog();
  85. if (this._DialogResult == System.Windows.Forms.DialogResult.OK)
  86. {
  87. if (this.ofdXsdFile.FileName != string.Empty)
  88. {
  89. this.txtXsdFile.Text = this.ofdXsdFile.FileName.ToString().Trim();
  90. }
  91. }
  92. }
  93. catch (Exception _Exception)
  94. {
  95. _ErrorMsg = string.Empty;
  96. _ErrorMsg = "*************** Error ***************" + "\r\n";
  97. _ErrorMsg = _ErrorMsg + " -> Event: bntSelectXsdFile_Click\r\n";
  98. _ErrorMsg = _ErrorMsg + " -> Message: " + _Exception.Message.ToString() + "\r\n";
  99. _ErrorMsg = _ErrorMsg + " -> Stack Trace: " + _Exception.StackTrace.ToString() + "\r\n";
  101. if (_Exception.InnerException != null)
  102. {
  103. _ErrorMsg = _ErrorMsg + " -> InnerException Message: " + _Exception.InnerException.Message.ToString() + "\r\n";
  104. _ErrorMsg = _ErrorMsg + " -> InnerException Stack Trace: " + _Exception.InnerException.StackTrace.ToString() + "\r\n";
  105. }
  107. _ErrorMsg = "*************************************";
  109. MessageBox.Show(_ErrorMsg, "XmlAndSchemaValidator", MessageBoxButtons.OK, MessageBoxIcon.Error);
  110. }
  111. }
  112. #endregion
  114. #region bntValidate_Click
  115. private void bntValidate_Click(object sender, EventArgs e)
  116. {
  117. string _ErrorMsg = string.Empty;
  118. string _ValidatorErrorMsg = string.Empty;
  119. FileInfo _FileInfo = null;
  121. try
  122. {
  123. this.txtValidationResult.Text = string.Empty;
  125. _FileInfo = new FileInfo(this.txtXmlFile.Text);
  126. this._Validator = new XmlAndSchemaValidator.Validator();
  127. _ValidatorErrorMsg = this._Validator.Validate(3, _FileInfo, System.Xml.XmlNodeType.Element, this.txtTargetNameSpace.Text, this.txtXsdFile.Text);
  129. if (_ValidatorErrorMsg != string.Empty)
  130. {
  131. _ErrorMsg = string.Empty;
  132. _ErrorMsg = "*************** Validation Error ***************" + "\r\n";
  133. _ErrorMsg = _ErrorMsg + "Validation Message: " + _ValidatorErrorMsg.ToString() + "\r\n";
  134. _ErrorMsg = _ErrorMsg + "************************************************";
  136. this.txtValidationResult.AppendText(_ErrorMsg);
  137. }
  138. else
  139. {
  140. _ErrorMsg = string.Empty;
  141. _ErrorMsg = "*************** Validation Sucess ***************" + "\r\n";
  142. _ErrorMsg = _ErrorMsg + "No Validation error ocorred!!!\r\n";
  143. _ErrorMsg = _ErrorMsg + "************************************************";
  145. this.txtValidationResult.AppendText(_ErrorMsg);
  146. }
  147. }
  148. catch (Exception _Exception)
  149. {
  150. _ErrorMsg = string.Empty;
  151. _ErrorMsg = "*************** Error ***************" + "\r\n";
  152. _ErrorMsg = _ErrorMsg + " -> Event: bntValidate_Click\r\n";
  153. _ErrorMsg = _ErrorMsg + " -> Message: " + _Exception.Message.ToString() + "\r\n";
  154. _ErrorMsg = _ErrorMsg + " -> Stack Trace: " + _Exception.StackTrace.ToString() + "\r\n";
  156. if (_Exception.InnerException != null)
  157. {
  158. _ErrorMsg = _ErrorMsg + " -> InnerException Message: " + _Exception.InnerException.Message.ToString() + "\r\n";
  159. _ErrorMsg = _ErrorMsg + " -> InnerException Stack Trace: " + _Exception.InnerException.StackTrace.ToString() + "\r\n";
  160. }
  162. _ErrorMsg = _ErrorMsg + "*************************************";
  164. MessageBox.Show(_ErrorMsg, "XmlAndSchemaValidator", MessageBoxButtons.OK, MessageBoxIcon.Error);
  165. }
  166. }
  167. #endregion
  168. #endregion
  169. }
  170. }
Finally the tester application should behave like this:
5. Conclution
Thank you for your care provided during reading my article and I hope you have been helped in some way.