Add XmlValidator class, enhance error messages in XMLDB, better error…

BackEnd/Data Access/Tables/DefaultTable.vb

@@ -36,6 +36,11 @@ Public Class DefaultTable
         Dim fileName As String = _table.GetStringProperty(TableProperty.FileName)
         Dim filePath As String = GetFilePath(fileName)
 
+        ' Validate that the XML file exists before attempting to load
+        If Not System.IO.File.Exists(filePath) Then
+            Throw New System.IO.FileNotFoundException($"XML file not found: {filePath}", fileName)
+        End If
+
         Dim sourceName As String = _table.GetStringProperty(TableProperty.SourceTableName)
         If sourceName Is Nothing Then
             'JMich Adding support for different rank levels of equipment

BackEnd/Data Access/XmlDB.vb

@@ -154,25 +154,61 @@ Public Class XmlDB
 
     Protected Sub EndInit()
         ds.AcceptChanges()
+
+        ' Proactive validation before enforcing constraints
+        Dim validator As New XmlValidator(ds)
+        If Not validator.ValidateAll() Then
+            ' Show detailed validation errors
+            Dim errorMessage As String = validator.GetFormattedErrors()
+            ErrorHandler.ShowError(errorMessage, "XML Validation Failed", MessageBoxIcon.Error)
+            ErrorHandler.TriggerFatalError()
+            Return
+        End If
+
         Try
             ds.EnforceConstraints = True
         Catch ex As ConstraintException
-            ErrorHandler.ShowError("One or more of your files contain invalid data.  Please fix the data and restart the editor.", "Error Loading Files", ex)
+            ' This is now a fallback - should rarely be hit due to proactive validation
+            Dim errMsg As New Text.StringBuilder()
+            errMsg.AppendLine("Constraint validation failed after proactive checks.")
+            errMsg.AppendLine("This may indicate a data race condition or complex constraint issue.")
+            errMsg.AppendLine()
+            errMsg.AppendLine("Error Details:")
+            errMsg.AppendLine(ex.Message)
+            errMsg.AppendLine()
+
             For Each t As DataTable In ds.Tables
                 If t.HasErrors Then
-                    Dim errStr As New Text.StringBuilder("Details:" & vbCrLf & vbCrLf)
                     Dim fileName As String = t.GetStringProperty(TableProperty.FileName)
                     If Not String.IsNullOrEmpty(fileName) Then
-                        errStr.Append("File: " & fileName & vbCrLf)
+                        errMsg.AppendLine("File: " & fileName)
                     Else
-                        errStr.Append("Table: " & t.TableName & vbCrLf)
+                        errMsg.AppendLine("Table: " & t.TableName)
                     End If
-                    For i As Integer = 0 To t.GetErrors.GetUpperBound(0)
-                        errStr.Append(vbCrLf & t.GetErrors(i).RowError)
+
+                    ' Enhanced error reporting with row numbers and column info
+                    Dim errorRows As DataRow() = t.GetErrors()
+                    For i As Integer = 0 To Math.Min(errorRows.GetUpperBound(0), 9) ' Limit to 10 errors
+                        Dim row As DataRow = errorRows(i)
+                        Dim rowIndex As Integer = t.Rows.IndexOf(row)
+                        errMsg.AppendLine($"  Row {rowIndex + 1}: {row.RowError}")
+
+                        ' Show which columns have errors
+                        For Each col As DataColumn In t.Columns
+                            If Not String.IsNullOrEmpty(row.GetColumnError(col)) Then
+                                errMsg.AppendLine($"    Column '{col.ColumnName}': {row.GetColumnError(col)}")
+                            End If
+                        Next
                     Next
-                    ErrorHandler.ShowError(errStr.ToString, "Error Loading Files", MessageBoxIcon.Exclamation)
+
+                    If errorRows.Length > 10 Then
+                        errMsg.AppendLine($"  ... and {errorRows.Length - 10} more error(s)")
+                    End If
+                    errMsg.AppendLine()
                 End If
             Next
+
+            ErrorHandler.ShowError(errMsg.ToString(), "Error Loading Files", MessageBoxIcon.Error, ex)
             ErrorHandler.TriggerFatalError()
         End Try
         ds.EndInit()
@@ -211,8 +247,19 @@ Public Class XmlDB
             End If
 
             If loadData Then
-                RaiseEvent LoadingTable(Me, fileName)
-                table.GetTableHandler.LoadData()
+                Try
+                    RaiseEvent LoadingTable(Me, fileName)
+                    table.GetTableHandler.LoadData()
+                Catch ex As System.IO.FileNotFoundException
+                    ErrorHandler.ShowError($"Failed to load '{fileName}': File not found.{vbCrLf}{vbCrLf}Path: {ex.FileName}", "File Not Found", MessageBoxIcon.Error, ex)
+                    Throw
+                Catch ex As Xml.XmlException
+                    ErrorHandler.ShowError($"Failed to load '{fileName}': Invalid XML format.{vbCrLf}{vbCrLf}Line {ex.LineNumber}, Position {ex.LinePosition}: {ex.Message}", "XML Format Error", MessageBoxIcon.Error, ex)
+                    Throw
+                Catch ex As Exception
+                    ErrorHandler.ShowError($"Failed to load '{fileName}': {ex.Message}{vbCrLf}{vbCrLf}Table: {table.TableName}", "Error Loading Table", MessageBoxIcon.Error, ex)
+                    Throw
+                End Try
             End If
 
         End If

BackEnd/Data Access/XmlValidator.vb

@@ -0,0 +1,276 @@
+Imports System.Data
+Imports System.Text
+
+Public Class XmlValidator
+    Private _dataSet As DataSet
+    Private _validationErrors As New List(Of ValidationError)
+
+    Public Sub New(dataSet As DataSet)
+        _dataSet = dataSet
+    End Sub
+
+    Public ReadOnly Property HasErrors As Boolean
+        Get
+            Return _validationErrors.Count > 0
+        End Get
+    End Property
+
+    Public ReadOnly Property Errors As List(Of ValidationError)
+        Get
+            Return _validationErrors
+        End Get
+    End ReadOnly Property
+
+    ''' <summary>
+    ''' Validates all data in the dataset before constraints are enforced
+    ''' </summary>
+    Public Function ValidateAll() As Boolean
+        _validationErrors.Clear()
+
+        ' Check for null/empty required fields
+        ValidateRequiredFields()
+
+        ' Check for duplicate primary keys
+        ValidatePrimaryKeys()
+
+        ' Check for foreign key violations
+        ValidateForeignKeys()
+
+        ' Check for unique constraint violations
+        ValidateUniqueConstraints()
+
+        Return Not HasErrors
+    End Function
+
+    ''' <summary>
+    ''' Validates a single table before loading
+    ''' </summary>
+    Public Function ValidateTable(table As DataTable) As Boolean
+        Dim startErrorCount = _validationErrors.Count
+
+        ValidateTableRequiredFields(table)
+        ValidateTablePrimaryKeys(table)
+        ValidateTableForeignKeys(table)
+        ValidateTableUniqueConstraints(table)
+
+        Return _validationErrors.Count = startErrorCount
+    End Function
+
+    Private Sub ValidateRequiredFields()
+        For Each table As DataTable In _dataSet.Tables
+            ValidateTableRequiredFields(table)
+        Next
+    End Sub
+
+    Private Sub ValidateTableRequiredFields(table As DataTable)
+        For Each col As DataColumn In table.Columns
+            If Not col.AllowDBNull AndAlso Not col.AutoIncrement Then
+                For i As Integer = 0 To table.Rows.Count - 1
+                    Dim row As DataRow = table.Rows(i)
+                    If row.RowState <> DataRowState.Deleted AndAlso IsDBNull(row(col)) Then
+                        AddError(table, i, col.ColumnName,
+                                "Required field is empty",
+                                ValidationErrorType.RequiredField)
+                    End If
+                Next
+            End If
+        Next
+    End Sub
+
+    Private Sub ValidatePrimaryKeys()
+        For Each table As DataTable In _dataSet.Tables
+            ValidateTablePrimaryKeys(table)
+        Next
+    End Sub
+
+    Private Sub ValidateTablePrimaryKeys(table As DataTable)
+        If table.PrimaryKey.Length = 0 Then Return
+
+        Dim pkValues As New Dictionary(Of String, Integer)
+        Dim pkColumns As String = String.Join(", ", table.PrimaryKey.Select(Function(c) c.ColumnName))
+
+        For i As Integer = 0 To table.Rows.Count - 1
+            Dim row As DataRow = table.Rows(i)
+            If row.RowState = DataRowState.Deleted Then Continue For
+
+            Dim keyValue As String = GetPrimaryKeyValue(row)
+            If pkValues.ContainsKey(keyValue) Then
+                AddError(table, i, pkColumns,
+                        $"Duplicate primary key value: {keyValue}. First occurrence at row {pkValues(keyValue) + 1}",
+                        ValidationErrorType.DuplicatePrimaryKey)
+            Else
+                pkValues.Add(keyValue, i)
+            End If
+        Next
+    End Sub
+
+    Private Sub ValidateForeignKeys()
+        For Each table As DataTable In _dataSet.Tables
+            ValidateTableForeignKeys(table)
+        Next
+    End Sub
+
+    Private Sub ValidateTableForeignKeys(table As DataTable)
+        For Each fk As ForeignKeyConstraint In table.Constraints.OfType(Of ForeignKeyConstraint)()
+            Dim parentTable As DataTable = fk.RelatedTable
+            Dim childColumns As String = String.Join(", ", fk.Columns.Select(Function(c) c.ColumnName))
+            Dim parentColumns As String = String.Join(", ", fk.RelatedColumns.Select(Function(c) c.ColumnName))
+
+            For i As Integer = 0 To table.Rows.Count - 1
+                Dim row As DataRow = table.Rows(i)
+                If row.RowState = DataRowState.Deleted Then Continue For
+
+                ' Build foreign key value
+                Dim fkValues(fk.Columns.Length - 1) As Object
+                For j As Integer = 0 To fk.Columns.Length - 1
+                    fkValues(j) = row(fk.Columns(j))
+                Next
+
+                ' Check if the value exists in parent table
+                Dim parentRow As DataRow = parentTable.Rows.Find(fkValues)
+                If parentRow Is Nothing AndAlso Not IsNullForeignKey(fkValues) Then
+                    Dim fkValueStr As String = String.Join(", ", fkValues.Select(Function(v) If(v Is Nothing, "NULL", v.ToString())))
+                    AddError(table, i, childColumns,
+                            $"Foreign key violation: Value '{fkValueStr}' does not exist in table '{parentTable.TableName}' column(s) '{parentColumns}'",
+                            ValidationErrorType.ForeignKeyViolation)
+                End If
+            Next
+        Next
+    End Sub
+
+    Private Sub ValidateUniqueConstraints()
+        For Each table As DataTable In _dataSet.Tables
+            ValidateTableUniqueConstraints(table)
+        Next
+    End Sub
+
+    Private Sub ValidateTableUniqueConstraints(table As DataTable)
+        For Each uc As UniqueConstraint In table.Constraints.OfType(Of UniqueConstraint)()
+            If uc.IsPrimaryKey Then Continue For ' Already checked
+
+            Dim uniqueValues As New Dictionary(Of String, Integer)
+            Dim columnNames As String = String.Join(", ", uc.Columns.Select(Function(c) c.ColumnName))
+
+            For i As Integer = 0 To table.Rows.Count - 1
+                Dim row As DataRow = table.Rows(i)
+                If row.RowState = DataRowState.Deleted Then Continue For
+
+                Dim keyValue As String = GetUniqueConstraintValue(row, uc.Columns)
+                If uniqueValues.ContainsKey(keyValue) Then
+                    AddError(table, i, columnNames,
+                            $"Unique constraint violation: Duplicate value '{keyValue}'. First occurrence at row {uniqueValues(keyValue) + 1}",
+                            ValidationErrorType.UniqueConstraintViolation)
+                Else
+                    uniqueValues.Add(keyValue, i)
+                End If
+            Next
+        Next
+    End Sub
+
+    Private Function GetPrimaryKeyValue(row As DataRow) As String
+        Dim values As New List(Of String)
+        For Each col As DataColumn In row.Table.PrimaryKey
+            values.Add(If(row(col) Is Nothing, "NULL", row(col).ToString()))
+        Next
+        Return String.Join("|", values)
+    End Function
+
+    Private Function GetUniqueConstraintValue(row As DataRow, columns As DataColumn()) As String
+        Dim values As New List(Of String)
+        For Each col As DataColumn In columns
+            values.Add(If(row(col) Is Nothing, "NULL", row(col).ToString()))
+        Next
+        Return String.Join("|", values)
+    End Function
+
+    Private Function IsNullForeignKey(values As Object()) As Boolean
+        For Each v In values
+            If v Is Nothing OrElse IsDBNull(v) Then Return True
+        Next
+        Return False
+    End Function
+
+    Private Sub AddError(table As DataTable, rowIndex As Integer, columnName As String, message As String, errorType As ValidationErrorType)
+        Dim fileName As String = table.GetStringProperty(TableProperty.FileName)
+        If String.IsNullOrEmpty(fileName) Then fileName = table.TableName
+
+        _validationErrors.Add(New ValidationError() With {
+            .FileName = fileName,
+            .TableName = table.TableName,
+            .RowIndex = rowIndex,
+            .ColumnName = columnName,
+            .Message = message,
+            .ErrorType = errorType
+        })
+    End Sub
+
+    Public Function GetFormattedErrors() As String
+        If Not HasErrors Then Return String.Empty
+
+        Dim sb As New StringBuilder()
+        sb.AppendLine("XML Validation Errors Found:")
+        sb.AppendLine()
+
+        ' Group errors by file
+        Dim errorsByFile = _validationErrors.GroupBy(Function(e) e.FileName)
+
+        For Each fileGroup In errorsByFile
+            sb.AppendLine($"File: {fileGroup.Key}")
+            sb.AppendLine(New String("-"c, 60))
+
+            ' Group by error type
+            Dim errorsByType = fileGroup.GroupBy(Function(e) e.ErrorType)
+
+            For Each typeGroup In errorsByType
+                sb.AppendLine($"  {GetErrorTypeDescription(typeGroup.Key)} ({typeGroup.Count()} error(s)):")
+
+                Dim maxErrors As Integer = 10 ' Limit display to first 10 errors per type
+                Dim displayCount As Integer = Math.Min(typeGroup.Count(), maxErrors)
+
+                For i As Integer = 0 To displayCount - 1
+                    Dim err = typeGroup.ElementAt(i)
+                    sb.AppendLine($"    Row {err.RowIndex + 1}, Column '{err.ColumnName}': {err.Message}")
+                Next
+
+                If typeGroup.Count() > maxErrors Then
+                    sb.AppendLine($"    ... and {typeGroup.Count() - maxErrors} more error(s)")
+                End If
+                sb.AppendLine()
+            Next
+        Next
+
+        Return sb.ToString()
+    End Function
+
+    Private Function GetErrorTypeDescription(errorType As ValidationErrorType) As String
+        Select Case errorType
+            Case ValidationErrorType.RequiredField
+                Return "Required Field Errors"
+            Case ValidationErrorType.DuplicatePrimaryKey
+                Return "Duplicate Primary Key Errors"
+            Case ValidationErrorType.ForeignKeyViolation
+                Return "Foreign Key Violations"
+            Case ValidationErrorType.UniqueConstraintViolation
+                Return "Unique Constraint Violations"
+            Case Else
+                Return "Other Errors"
+        End Select
+    End Function
+End Class
+
+Public Class ValidationError
+    Public Property FileName As String
+    Public Property TableName As String
+    Public Property RowIndex As Integer
+    Public Property ColumnName As String
+    Public Property Message As String
+    Public Property ErrorType As ValidationErrorType
+End Class
+
+Public Enum ValidationErrorType
+    RequiredField
+    DuplicatePrimaryKey
+    ForeignKeyViolation
+    UniqueConstraintViolation
+    Other
+End Enum