WPF对我来说还是新手，只用了几个星期。我从DataTemplate小区获取DataGrid时遇到了一些问题。我试过的每一种方式都给了我一个空洞的对象。找到了一些这方面的一般例子后，我无法在我的案例中找到它。他们中没有一个人像我一样试图这样做，我必须放弃功能，使其像我所见的例子一样。
我有DataGrid绑定到sql DataSet。 DataGrid只有一个DataGridTemplateColumn。它由基于DataTemplateSelector的自定义类提供。 DataGridTemplateColumn有几个控件绑定到DataSet中的字段，并且它有一个未绑定的控件。那个未绑定的控件是问题的根源。我需要得到用户放入一个未绑定控件的内容。他们只能这样做才能获得该单元格DataTemplate。
在sInsertSurveyResponse()中，当我尝试取出DataTemplate时，我得到一个空白对象，即VB术语中的Nothing。我尝试在单元级别和行级别获取模板但没有成功。
有人能说清楚为什么这不起作用吗？此外，当我在编写MS代码时使用VB工作时，我知道足够的C＃来理解使用该语言的响应，所以不要忍住。谢谢。
下面包含完整的代码。
XAML
<Window x:Class="MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApplication1"
mc:Ignorable="d"
Title="Survey" Height="450" Width="550" Loaded="Window_Loaded">
<Grid x:Name="gridSurvey" Background="#66FFFFFF" >
<GroupBox x:Name="gbSurvey" Header="Please answer a few questions" Background="#FF3C9910" BorderBrush="Black" Width="500" Height="400" VerticalAlignment="Center" HorizontalAlignment="Center" >
<GroupBox.HeaderTemplate>
<DataTemplate>
<Grid>
<Border Name="Border" Margin="-2,0,-4,0" Padding="10,2" CornerRadius="5" BorderThickness="2" BorderBrush="#FF000000" Background="{Binding Background, Mode=OneWay, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type GroupBox}}}" >
<ContentPresenter x:Name="GridHeaderContent" Content="{TemplateBinding Content}" VerticalAlignment="Center" HorizontalAlignment="Center" />
</Border>
<Rectangle Height="12" Width="5" Margin="-2,0,0,0" StrokeThickness="0" VerticalAlignment="Bottom" HorizontalAlignment="Left" Fill="{Binding Background, Mode=OneWay, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type GroupBox}}}"/>
<Rectangle Height="5" Margin="0,0,0,-2" StrokeThickness="0" VerticalAlignment="Bottom" HorizontalAlignment="Stretch" Fill="{Binding Background, Mode=OneWay, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type GroupBox}}}"/>
<Rectangle Height="12" Width="5" Margin="0,0,-4,0" StrokeThickness="0" VerticalAlignment="Bottom" HorizontalAlignment="Right" Fill="{Binding Background, Mode=OneWay, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type GroupBox}}}"/>
</Grid>
</DataTemplate>
</GroupBox.HeaderTemplate>
<GroupBox.Effect>
<DropShadowEffect Opacity="0.5"/>
</GroupBox.Effect>
<Grid>
<DataGrid x:Name="dataGridSurveyQuestions" ItemsSource="{Binding Path=SurveyQuestionsDataBinding}" Margin="8,2,8,47" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalScrollBarVisibility="Hidden" HeadersVisibility="None" IsReadOnly="True" AutoGenerateColumns="False" Background="{Binding Background, Mode=OneWay, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type GroupBox}}}" BorderThickness="0" GridLinesVisibility="None" >
<DataGrid.Resources>
<DataTemplate x:Key="dataTemplateQuestionType1" >
<Grid Width="475" Background="{Binding Background, Mode=OneWay, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type GroupBox}}}">
<Label x:Name="QID" Content="{Binding QID}" Visibility="Collapsed" />
<Label x:Name="TID" Content="{Binding TID}" Visibility="Collapsed" />
<TextBlock x:Name="tbQuestion" Text="{Binding Question}" Margin="10,10,0,0" Width="325" Padding="0" HorizontalAlignment="Left" VerticalAlignment="Top" FontSize="14" FontWeight="Normal" TextWrapping="Wrap" />
<ComboBox x:Name="surveyResponse" ToolTip="{Binding Instructions}" Width="125" Height="29" Margin="0,5,20,5" HorizontalAlignment="Right" VerticalAlignment="Top" >
<ComboBoxItem Tag="1" Content="1 (Best)"/>
<ComboBoxItem Tag="2" Content="2"/>
<ComboBoxItem Tag="3" Content="3 (Average)"/>
<ComboBoxItem Tag="4" Content="4"/>
<ComboBoxItem Tag="5" Content="5 (Worst)"/>
</ComboBox>
</Grid>
</DataTemplate>
<DataTemplate x:Key="dataTemplateQuestionType2" >
<Grid Width="475" Background="{Binding Background, Mode=OneWay, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type GroupBox}}}">
<Label x:Name="QID" Content="{Binding QID}" Visibility="Collapsed" />
<Label x:Name="TID" Content="{Binding TID}" Visibility="Collapsed" />
<TextBlock x:Name="tbQuestion" Text="{Binding Question}" Margin="10,10,0,0" Width="325" Padding="0" HorizontalAlignment="Left" VerticalAlignment="Top" FontSize="14" FontWeight="Normal" TextWrapping="Wrap" />
<ComboBox x:Name="surveyResponse" ToolTip="{Binding Instructions}" Width="125" Height="29" Margin="0,5,20,5" HorizontalAlignment="Right" VerticalAlignment="Top" >
<ComboBoxItem Tag="1" Content="1 (Worst)"/>
<ComboBoxItem Tag="2" Content="2"/>
<ComboBoxItem Tag="3" Content="3 (Average)"/>
<ComboBoxItem Tag="4" Content="4"/>
<ComboBoxItem Tag="5" Content="5 (Best)"/>
</ComboBox>
</Grid>
</DataTemplate>
<DataTemplate x:Key="dataTemplateQuestionType3" >
<Grid Width="475" Background="{Binding Background, Mode=OneWay, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type GroupBox}}}">
<Label x:Name="QID" Content="{Binding QID}" Visibility="Collapsed" />
<Label x:Name="TID" Content="{Binding TID}" Visibility="Collapsed" />
<TextBlock x:Name="tbQuestion" Text="{Binding Question}" Margin="10,10,0,0" Width="325" Padding="0" HorizontalAlignment="Left" VerticalAlignment="Top" FontSize="14" FontWeight="Normal" TextWrapping="Wrap" />
<ComboBox x:Name="surveyResponse" ToolTip="{Binding Instructions}" Width="125" Height="29" Margin="0,5,20,5" HorizontalAlignment="Right" VerticalAlignment="Top" >
<ComboBoxItem Tag="1" Content="1 (Best)"/>
<ComboBoxItem Tag="2" Content="2"/>
<ComboBoxItem Tag="3" Content="3"/>
<ComboBoxItem Tag="4" Content="4"/>
<ComboBoxItem Tag="5" Content="5 (Average)"/>
<ComboBoxItem Tag="6" Content="6"/>
<ComboBoxItem Tag="7" Content="7"/>
<ComboBoxItem Tag="8" Content="8"/>
<ComboBoxItem Tag="9" Content="9"/>
<ComboBoxItem Tag="10" Content="10 (Worst)"/>
</ComboBox>
</Grid>
</DataTemplate>
<DataTemplate x:Key="dataTemplateQuestionType4" >
<Grid Width="475" Background="{Binding Background, Mode=OneWay, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type GroupBox}}}">
<Label x:Name="QID" Content="{Binding QID}" Visibility="Collapsed" />
<Label x:Name="TID" Content="{Binding TID}" Visibility="Collapsed" />
<TextBlock x:Name="tbQuestion" Text="{Binding Question}" Margin="10,10,0,0" Width="325" Padding="0" HorizontalAlignment="Left" VerticalAlignment="Top" FontSize="14" FontWeight="Normal" TextWrapping="Wrap" />
<ComboBox x:Name="surveyResponse" ToolTip="{Binding Instructions}" Width="125" Height="29" Margin="0,5,20,5" HorizontalAlignment="Right" VerticalAlignment="Top" >
<ComboBoxItem Tag="1" Content="1 (Worst)"/>
<ComboBoxItem Tag="2" Content="2"/>
<ComboBoxItem Tag="3" Content="3"/>
<ComboBoxItem Tag="4" Content="4"/>
<ComboBoxItem Tag="5" Content="5 (Average)"/>
<ComboBoxItem Tag="6" Content="6"/>
<ComboBoxItem Tag="7" Content="7"/>
<ComboBoxItem Tag="8" Content="8"/>
<ComboBoxItem Tag="9" Content="9"/>
<ComboBoxItem Tag="10" Content="10 (Best)"/>
</ComboBox>
</Grid>
</DataTemplate>
<DataTemplate x:Key="dataTemplateQuestionType5" >
<Grid Width="475" Background="{Binding Background, Mode=OneWay, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type GroupBox}}}">
<Label x:Name="QID" Content="{Binding QID}" Visibility="Collapsed" />
<Label x:Name="TID" Content="{Binding TID}" Visibility="Collapsed" />
<TextBlock x:Name="tbQuestion" Text="{Binding Question}" Margin="10,10,0,0" Width="325" Padding="0" HorizontalAlignment="Left" VerticalAlignment="Top" FontSize="14" FontWeight="Normal" TextWrapping="Wrap" />
<TextBox x:Name="surveyResponse" ToolTip="{Binding Instructions}" Width="125" Height="29" Margin="0,5,20,5" HorizontalAlignment="Right" VerticalAlignment="Top" />
</Grid>
</DataTemplate>
</DataGrid.Resources>
<DataGrid.CellStyle>
<Style TargetType="{x:Type DataGridCell}">
<Setter Property="BorderThickness" Value="0"/>
</Style>
</DataGrid.CellStyle>
<DataGrid.Columns>
<DataGridTemplateColumn>
<DataGridTemplateColumn.CellTemplateSelector>
<local:SurveyResponseTemplateSelector
Type1Template="{StaticResource dataTemplateQuestionType1}"
Type2Template="{StaticResource dataTemplateQuestionType2}"
Type3Template="{StaticResource dataTemplateQuestionType3}"
Type4Template="{StaticResource dataTemplateQuestionType4}"
Type5Template="{StaticResource dataTemplateQuestionType5}"/>
</DataGridTemplateColumn.CellTemplateSelector>
</DataGridTemplateColumn>
</DataGrid.Columns>
</DataGrid>
<Button x:Name="btnCancelSurvey" Content="Cancel" Width="85" HorizontalAlignment="Left" Margin="80,0,0,10" VerticalAlignment="Bottom" />
<Button x:Name="btnSaveSurvey" Content="Done" Width="85" HorizontalAlignment="Right" Margin="0,0,80,10" VerticalAlignment="Bottom" />
</Grid>
</GroupBox>
</Grid>
</Window>
VB
Imports MySql.Data.MySqlClient
Imports System.Data
Imports System.Windows.Controls.Primitives
Public Class SurveyResponseTemplateSelector
Inherits DataTemplateSelector
Public Property Type1Template() As DataTemplate
Get
Return m_Type1Template
End Get
Set
m_Type1Template = Value
End Set
End Property
Private m_Type1Template As DataTemplate
Public Property Type2Template() As DataTemplate
Get
Return m_Type2Template
End Get
Set
m_Type2Template = Value
End Set
End Property
Private m_Type2Template As DataTemplate
Public Property Type3Template() As DataTemplate
Get
Return m_Type3Template
End Get
Set
m_Type3Template = Value
End Set
End Property
Private m_Type3Template As DataTemplate
Public Property Type4Template() As DataTemplate
Get
Return m_Type4Template
End Get
Set
m_Type4Template = Value
End Set
End Property
Private m_Type4Template As DataTemplate
Public Property Type5Template() As DataTemplate
Get
Return m_Type5Template
End Get
Set
m_Type5Template = Value
End Set
End Property
Private m_Type5Template As DataTemplate
Public Overrides Function SelectTemplate(item As Object, container As DependencyObject) As DataTemplate
Dim drvItem As DataRowView = TryCast(item, DataRowView)
If drvItem IsNot Nothing Then
Dim TID As Integer = drvItem.Row.ItemArray(1)
Select Case TID
Case 1
Return Type1Template
Exit Select
Case 2
Return Type2Template
Exit Select
Case 3
Return Type3Template
Exit Select
Case 4
Return Type4Template
Exit Select
Case 5
Return Type5Template
Exit Select
Case Else
Return MyBase.SelectTemplate(item, container)
End Select
Else
Return MyBase.SelectTemplate(item, container)
End If
End Function
End Class
Class MainWindow
Dim gConn As MySqlConnection = New MySqlConnection("server=localhost;user id=xxxxx;password=xxxxxx;database=xxxxx")
Private Function fFindVisualChild(Of childItem As DependencyObject)(ByVal obj As DependencyObject) As childItem
Dim i As Integer
For i = 0 To VisualTreeHelper.GetChildrenCount(obj) - 1
Dim child As DependencyObject = VisualTreeHelper.GetChild(obj, i)
If ((Not child Is Nothing) And (TypeOf child Is childItem)) Then
Return child
End If
Dim childOfChild As childItem = Me.fFindVisualChild(Of childItem)(child)
If (Not childOfChild Is Nothing) Then
Return childOfChild
End If
Next i
Return Nothing
End Function
Private Sub sInsertSurveyResponse()
' Note to self: This is full of testing code, clean it up later.
Try
gConn.Open()
Using sqlTran As MySqlTransaction = gConn.BeginTransaction()
Try
Dim allOK As Boolean = True
Dim affectedRowKnt As Integer = 0
Dim errorMessage As String = ""
Dim insertResponseSQL As String = "INSERT INTO meals.tbl_survey_responses(int_Question_ID,char_Response) " +
"VALUES (@int_Question_ID,@char_Response);"
Using cmd As New MySqlCommand(insertResponseSQL, gConn, sqlTran)
For x As Integer = 0 To dataGridSurveyQuestions.Items.Count - 1
Dim row As DataGridRow = DirectCast(dataGridSurveyQuestions.ItemContainerGenerator.ContainerFromItem(dataGridSurveyQuestions.Items.Item(x)), DataGridRow)
Dim questionID As String = ""
Dim surveyResponse As String = ""
If row IsNot Nothing Then
Dim presenter As DataGridCellsPresenter = fFindVisualChild(Of DataGridCellsPresenter)(row)
Dim template As DataTemplate = presenter.ItemTemplate
' Testing code, try to get the controls from the cell's item template, this FAILS
If template IsNot Nothing Then
Dim QID As Label = DirectCast(template.FindName("QID", presenter), Label)
Dim TID As Label = DirectCast(template.FindName("TID", presenter), Label)
questionID = QID.Content
If Not TID.Content.Equals("5") Then
surveyResponse = DirectCast(DirectCast(template.FindName("surveyResponse", presenter), ComboBox).SelectedItem, ComboBoxItem).Tag
Else
surveyResponse = DirectCast(template.FindName("surveyResponse", presenter), TextBox).Text
End If
Else
Dim presenter2 As DataGridDetailsPresenter = fFindVisualChild(Of DataGridDetailsPresenter)(row)
Dim template2 As DataTemplate = presenter2.ContentTemplate
' Testing code, try to get the controls from the row's content template, this also FAILS
If template IsNot Nothing Then
Dim QID As Label = DirectCast(template.FindName("QID", presenter), Label)
Dim TID As Label = DirectCast(template.FindName("TID", presenter), Label)
questionID = QID.Content
If Not TID.Content.Equals("5") Then
surveyResponse = DirectCast(DirectCast(template.FindName("surveyResponse", presenter), ComboBox).SelectedItem, ComboBoxItem).Tag
Else
surveyResponse = DirectCast(template.FindName("surveyResponse", presenter), TextBox).Text
End If
Else
allOK = False
MessageBox.Show("Got NOTHING in either template...")
End If
End If
Else
allOK = False
MessageBox.Show("Got NOTHING in ROW...")
End If
If allOK Then
cmd.Parameters.AddWithValue("@int_Question_ID", questionID)
cmd.Parameters.AddWithValue("@char_Response", surveyResponse)
affectedRowKnt = cmd.ExecuteNonQuery()
cmd.Parameters.Clear()
If affectedRowKnt = 0 Then Exit For
End If
Next x
End Using
If affectedRowKnt = 0 Then
allOK = False
errorMessage = "Unable to add all response records."
End If
If allOK Then
sqlTran.Commit()
Else
MessageBox.Show(errorMessage, "Save Survey Response Failed", MessageBoxButton.OK, MessageBoxImage.Error)
sqlTran.Rollback()
End If
Catch ex As Exception
MessageBox.Show(ex.ToString, "Error Message", MessageBoxButton.OK, MessageBoxImage.Error)
sqlTran.Rollback()
End Try
End Using
Catch ex As Exception
MessageBox.Show(ex.ToString, "Error Message", MessageBoxButton.OK, MessageBoxImage.Error)
Finally
gConn.Close()
End Try
End Sub
Private Sub sRefreshSurveyQuestions()
Try
gConn.Open()
Dim sql As String = "SELECT q.int_Question_ID QID, q.int_Question_Type_ID TID, q.char_Question Question, t.char_Title Instructions
FROM meals.tbl_survey_questions q,
meals.tbl_survey_question_types t
WHERE q.bool_Active = 1
AND q.int_Question_Type_ID = t.int_Question_Type_ID
ORDER BY q.char_SortOrder, q.char_Question;"
Dim cmd As MySqlCommand = New MySqlCommand(sql, gConn)
Dim adp As MySqlDataAdapter = New MySqlDataAdapter(cmd)
Dim ds As DataSet = New DataSet()
adp.Fill(ds, "SurveyQuestionsDataBinding")
dataGridSurveyQuestions.DataContext = ds
Catch ex As Exception
MessageBox.Show(ex.ToString, "Error Message", MessageBoxButton.OK, MessageBoxImage.Error)
Finally
gConn.Close()
End Try
End Sub
Private Sub btnSaveSurvey_Click(sender As Object, e As RoutedEventArgs) Handles btnSaveSurvey.Click
sInsertSurveyResponse()
End Sub
Private Sub btnCancelSurvey_Click(sender As Object, e As RoutedEventArgs) Handles btnCancelSurvey.Click
sRefreshSurveyQuestions()
End Sub
Private Sub Window_Loaded(sender As Object, e As RoutedEventArgs)
sRefreshSurveyQuestions()
End Sub
End Class
SQL
CREATE TABLE tbl_survey_questions (
int_Question_ID INT(10) NOT NULL AUTO_INCREMENT,
int_Question_Type_ID INT(10) NOT NULL,
char_Question VARCHAR(1000) NOT NULL,
char_SortOrder VARCHAR(5) DEFAULT 'MMMMM',
bool_Active BOOLEAN NOT NULL,
PRIMARY KEY (int_Question_ID)
);
CREATE TABLE tbl_survey_question_types (
int_Question_Type_ID INT(10) NOT NULL AUTO_INCREMENT,
char_Title VARCHAR(100) NOT NULL,
PRIMARY KEY (int_Question_Type_ID)
);
CREATE TABLE tbl_survey_responses (
int_Response_ID INT(10) NOT NULL AUTO_INCREMENT,
dt_Response_Datetime datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
int_Question_ID INT(10) NOT NULL,
char_Response VARCHAR(100) NOT NULL,
PRIMARY KEY (int_Response_ID)
);
insert into tbl_survey_question_types (int_Question_Type_ID, char_Title)
VALUES (1, 'Ranked 1 to 5, with 1 as the most favorable response.');
insert into tbl_survey_question_types (int_Question_Type_ID, char_Title)
VALUES (2, 'Ranked 1 to 5, with 1 as the least favorable response.');
insert into tbl_survey_question_types (int_Question_Type_ID, char_Title)
VALUES (3, 'Ranked 1 to 10, with 1 as the most favorable response.');
insert into tbl_survey_question_types (int_Question_Type_ID, char_Title)
VALUES (4, 'Ranked 1 to 10, with 1 as the least favorable response.');
insert into tbl_survey_question_types (int_Question_Type_ID, char_Title)
VALUES (5, 'Free form, fill in with your text.');
insert into tbl_survey_questions (int_Question_Type_ID, char_Question, char_SortOrder, bool_Active)
values (4, 'At the moment how would you rate thing 1?', 'MMAMM', true);
insert into tbl_survey_questions (int_Question_Type_ID, char_Question, char_SortOrder, bool_Active)
values (1, 'At the moment how would you rate thing 2?', 'MMDMM', true);
insert into tbl_survey_questions (int_Question_Type_ID, char_Question, char_SortOrder, bool_Active)
values (3, 'At the moment how would you rate thing 3?', 'MMEMM', true);
insert into tbl_survey_questions (int_Question_Type_ID, char_Question, char_SortOrder, bool_Active)
values (3, 'At the moment how would you rate thing 4?', 'MMCMM', true);
insert into tbl_survey_questions (int_Question_Type_ID, char_Question, char_SortOrder, bool_Active)
values (2, 'At the moment how would you rate thing 5?', 'MMBMM', true);
答案 0 :(得分：0)
据我所知，我的DataTemplate中找不到DataGrid。所以，我已经改变了齿轮，然后分开DataGridCell的视觉控制树，以便直接访问未绑定的控件。通过名称和类型获取子元素是必需的，因此我用fFindVisualChildByName（）替换了我使用的fFindVisualChild（）。
Private Function fFindVisualChildByName(Of childItem As DependencyObject)(parent As DependencyObject, childName As String) As childItem
Dim foundChild As childItem = Nothing
If parent IsNot Nothing Then
For i As Integer = 0 To VisualTreeHelper.GetChildrenCount(parent) - 1
Dim child = VisualTreeHelper.GetChild(parent, i)
Dim childType As childItem = TryCast(child, childItem)
If childType Is Nothing Then
foundChild = fFindVisualChildByName(Of childItem)(child, childName)
If foundChild IsNot Nothing Then
Exit For
End If
ElseIf Not String.IsNullOrEmpty(childName) Then
Dim frameworkElement = TryCast(child, FrameworkElement)
If frameworkElement IsNot Nothing AndAlso frameworkElement.Name = childName Then
foundChild = DirectCast(child, childItem)
Exit For
End If
Else
foundChild = DirectCast(child, childItem)
Exit For
End If
Next
End If
Return foundChild
End Function
现在，这是一个递归函数，所以它可能是一个资源匮乏，应该谨慎使用。出于这个原因，我尽量避免从树顶使用它。在fFindVisualChildByName（）到位后，我更改了sInsertSurveyResponse（），删除了测试代码并使用了新函数。
Private Sub sInsertSurveyResponse()
Try
gConn.Open()
Using sqlTran As MySqlTransaction = gConn.BeginTransaction()
Try
Dim allOK As Boolean = True
Dim rows As Integer = 0
Dim newID As Int16 = 0
Dim errorMessage As String = ""
Dim getNextIDSQL As String = "SELECT IfNull(MAX(int_Response_ID),0)+1 FROM meals.tbl_survey_responses;"
Dim insertResponseSQL As String = "INSERT INTO meals.tbl_survey_responses(int_Response_ID,int_Question_ID,char_Response) " +
"VALUES (@int_Response_ID,@int_Question_ID,@char_Response);"
Using cmd As New MySqlCommand(getNextIDSQL, gConn, sqlTran)
newID = Convert.ToInt16(cmd.ExecuteScalar())
End Using
Using cmd As New MySqlCommand(insertResponseSQL, gConn, sqlTran)
For x As Integer = 0 To dataGridSurveyQuestions.Items.Count - 1
Dim dgRow As DataGridRow = DirectCast(dataGridSurveyQuestions.ItemContainerGenerator.ContainerFromItem(dataGridSurveyQuestions.Items.Item(x)), DataGridRow)
Dim dgCell As DataGridCell = fFindVisualChildByName(Of DataGridCell)(dgRow, Nothing)
Dim QID As Label = fFindVisualChildByName(Of Label)(dgCell, "QID")
Dim TID As Label = fFindVisualChildByName(Of Label)(dgCell, "TID")
Dim surveyResponse As String = ""
If Not TID.Content.Equals("5") Then
Dim cbResponse As ComboBox = fFindVisualChildByName(Of ComboBox)(dgCell, "surveyResponse")
If cbResponse.SelectedIndex >= 0 Then
surveyResponse = DirectCast(cbResponse.SelectedItem, ComboBoxItem).Tag
End If
Else
Dim tbResponse As TextBox = fFindVisualChildByName(Of TextBox)(dgCell, "surveyResponse")
surveyResponse = tbResponse.Text
End If
If surveyResponse.Length > 0 Then
cmd.Parameters.AddWithValue("@int_Response_ID", newID.ToString())
cmd.Parameters.AddWithValue("@int_Question_ID", QID.Content)
cmd.Parameters.AddWithValue("@char_Response", surveyResponse)
rows = cmd.ExecuteNonQuery()
If rows = 0 Then
allOK = False
errorMessage = "Unable to add all response records."
Exit For
Else
cmd.Parameters.Clear()
End If
Else
allOK = False
errorMessage = "Blank responses are not valid. Save failed."
Exit For
End If
Next x
End Using
If allOK Then
sqlTran.Commit()
Else
MessageBox.Show(errorMessage, "Save Survey Response Failed", MessageBoxButton.OK, MessageBoxImage.Error)
sqlTran.Rollback()
End If
Catch ex As Exception
MessageBox.Show(ex.ToString, "Error Message", MessageBoxButton.OK, MessageBoxImage.Error)
sqlTran.Rollback()
End Try
End Using
Catch ex As Exception
MessageBox.Show(ex.ToString, "Error Message", MessageBoxButton.OK, MessageBoxImage.Error)
Finally
gConn.Close()
End Try
End Sub
最后，我从tbl_survey_responses和自动编号中删除了主键。从答案的角度来看，这并不重要，但是如果以此处的代码为例。我喜欢有效的例子，我不会像我一样喜欢看。
所以，这就是我为自己找到的答案。我仍然不知道为什么DataTemplate在我的情况下是空的，而不是为了其他人。我只能猜测它与我使用DataTemplateSelector有关。