我创建了一个非常简单的数据库应用程序，因为我对WPF很新。最终我能够在winform中使用导航按钮（不使用数据绑定）。我遇到了一个问题，我希望这是一个非常简单的问题，但我又一次不知道？
问题
当我使用导航按钮时，数据没有显示在combox中，但似乎文本框没有问题，它基本上显示为空。我有一个listview所以当CUD操作时显示整个记录。我错过了什么吗？
我创建的部分类和showdata方法
public partial class MainWindow : Window
{
SqlConnection mconn;
int MaxRows = 0;
int rno;
DataSet ds;
private void MaxRow()
{
MaxRows = ds.Tables[0].Rows.Count;
}
}
public void ShowData()
{
try
{
//pardon me this looks rather tacty
SqlCommand comm = new SqlCommand("Select * from tblTableB", mconn);
DataTable dt = new DataTable();
SqlDataAdapter da = new SqlDataAdapter(comm);
da.Fill(dt);
listView1.DataContext = dt.DefaultView;
da = new SqlDataAdapter("select * from tblTableB", mconn);
ds = new DataSet();
da.Fill(ds, "TestDatabaseB");
da.Update(ds, "TestDatabaseB");
this.MaxRow();
txtID.Text = ds.Tables[0].Rows[rno][0].ToString();
txtName.Text = ds.Tables[0].Rows[rno][1].ToString();
cBHealthDetails.Text = ds.Tables[0].Rows[rno][2].ToString(); //data not showing
when navigation buttons are used. CB is showning empty
}
catch (Exception ex)
{
MessageBox.Show("Error: " + ex.Message);
}
}
导航方法示例
private void PreRec_Click(object sender, RoutedEventArgs e)
{
if (ds.Tables[0].Rows.Count > 0)
{
if (rno > 0)
{
rno--;
ShowData();
}
}
}
private void NxtRec_Click(object sender, RoutedEventArgs e)
{
if (ds.Tables[0].Rows.Count > 0)
{
if (rno < ds.Tables[0].Rows.Count - 1)
{
rno++;
ShowData();
}
}
}
XAML代码
<Window x:Class="WpfApplication4.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="381" Width="406" Loaded="Window_Loaded">
<Grid>
<Grid Height="342" HorizontalAlignment="Left" Name="grid1" VerticalAlignment="Top" Width="384">
<ListView Height="134" HorizontalAlignment="Left" Name="listView1" ItemsSource="{Binding}" VerticalAlignment="Top" Width="384">
<ListView.View>
<GridView>
<GridViewColumn Header="ID" DisplayMemberBinding="{Binding Path=ID}"></GridViewColumn>
<GridViewColumn Header="Name" DisplayMemberBinding="{Binding Path=Name}"></GridViewColumn>
<GridViewColumn Header="Health Details" DisplayMemberBinding="{Binding Path=HealthDetails}"></GridViewColumn>
</GridView>
</ListView.View>
</ListView>
<Label Content="Name" Height="28" HorizontalAlignment="Left" Margin="7,181,0,0" Name="label1" VerticalAlignment="Top" />
<Label Content="Health Details" Height="28" HorizontalAlignment="Left" Margin="7,215,0,0" Name="label2" VerticalAlignment="Top" />
<TextBox Height="23" HorizontalAlignment="Left" Margin="102,152,0,0" Name="txtID" VerticalAlignment="Top" Width="120" DataContext="{Binding ElementName=listView1,Path=SelectedItem}" Text="{Binding Path=ID}" IsReadOnly="True" Background="#26000000"></TextBox>
<TextBox Height="23" HorizontalAlignment="Left" Margin="102,186,0,0" Name="txtName" VerticalAlignment="Top" Width="243" DataContext="{Binding ElementName=listView1,Path=SelectedItem}" Text="{Binding Path=Name}" />
<ComboBox Height="23" HorizontalAlignment="Left" Margin="102,220,0,0" Name="cBHealthDetails" VerticalAlignment="Top" Width="120" DataContext="{Binding ElementName=listView1,Path=SelectedItem}" Text="{Binding Path=HealthDetails}">
<ComboBoxItem Content="Yes" />
<ComboBoxItem Content="No" />
</ComboBox>
<Button Content="New" Height="23" HorizontalAlignment="Left" Margin="25,262,0,0" Name="btnNew" VerticalAlignment="Top" Width="75" Click="btnNew_Click" />
<Button Content="Insert" Height="23" HorizontalAlignment="Left" Margin="111,262,0,0" Name="btnInsert" VerticalAlignment="Top" Width="75" Click="btnInsert_Click"></Button>
<Button Content="Update" Height="23" HorizontalAlignment="Left" Margin="197,262,0,0" Name="btnUpdate" VerticalAlignment="Top" Width="75" />
<Button Content="Delete" Height="23" HorizontalAlignment="Left" Margin="280,262,0,0" Name="btnDelete" VerticalAlignment="Top" Width="75" />
<Button Content="<<" Height="23" HorizontalAlignment="Left" Margin="25,301,0,0" Name="FirstRec" VerticalAlignment="Top" Width="75" Click="FirstRec_Click" />
<Button Content="<" Height="23" HorizontalAlignment="Left" Margin="111,301,0,0" Name="PreRec" VerticalAlignment="Top" Width="75" Click="PreRec_Click" />
<Button Content=">" Height="23" HorizontalAlignment="Right" Margin="0,301,112,0" Name="NxtRec" VerticalAlignment="Top" Width="75" Click="NxtRec_Click" />
<Button Content=">>" Height="23" HorizontalAlignment="Left" Margin="280,301,0,0" Name="LastRec" VerticalAlignment="Top" Width="75" Click="LastRec_Click" />
<Label Content="ID" Height="28" HorizontalAlignment="Left" Margin="11,147,0,0" Name="label3" VerticalAlignment="Top" />
</Grid>
</Grid>
非常感谢
更新1
Windows已加载
private void Window_Loaded(object sender, RoutedEventArgs e)
{
ShowData();
}
void ShowData()
{
try
{
SqlCommand comm = new SqlCommand("Select * from tblTableB", mconn);
DataTable dt = new DataTable();
SqlDataAdapter da = new SqlDataAdapter(comm);
da.Fill(dt);
listView1.DataContext = dt.DefaultView;
}
catch (Exception ex)
{
MessageBox.Show("Error: " + ex.Message);
}
}
private void btnShowAll_Click(object sender, RoutedEventArgs e)
{
da = new SqlDataAdapter("select * from tblTableB", mconn);
ds = new DataSet();
da.Fill(ds, "tblTableB");
da.Update(ds, "tblTableB");
this.MaxRow();
txtID.Text = ds.Tables[0].Rows[rno][0].ToString(); //rno["ID"]
txtName.Text = ds.Tables[0].Rows[rno][1].ToString(); //rno["Name"]
cBHealthDetails.Text = ds.Tables[0].Rows[rno][2].ToString(); //also tried by replacing
//rno["HealthDetails"].ToString();
}
XAML代码
<TextBox Height="23" HorizontalAlignment="Left" Margin="102,152,0,0" Name="txtID" VerticalAlignment="Top" Width="120" IsReadOnly="True" Background="#26000000"></TextBox>
<TextBox Height="23" HorizontalAlignment="Left" Margin="102,186,0,0" Name="txtName" VerticalAlignment="Top" Width="243" />
<ComboBox Height="23" HorizontalAlignment="Left" Margin="102,220,0,0" Name="cBHealthDetails" VerticalAlignment="Top" Width="120">
<ComboBoxItem Content="Yes"></ComboBoxItem>
<ComboBoxItem Content="No"></ComboBoxItem>
</ComboBox>
因此，无论是wpf combox还是combox属性都存在错误，我需要做一些我错过的事情。我在属性中唯一做的就是...... Items＆gt;收集并添加内容一个为是，另一个为否。
我还在研究，一旦找到解决方案，我会更新
找到解决方案
似乎在wpf进程中，或者架构设计与winobox有很大不同。以下代码无效
cBHealthDetails.Text = ds.Tables[0].Rows[rno][2].ToString();
我还必须使用条件循环来消除重复值。
所以下面这段代码对我来说对我所发现的here的combox有用，并感谢sohel khalifa ......
for (int intCount = 0; intCount < ds.Tables[0].Rows.Count; intCount++)
{
var val = ds.Tables[0].Rows[intCount]["Health"].ToString();
//check if it already exists
if (!cbHealth.Items.Contains(val))
{
cbHealth.Items.Add(val);
}
}
我甚至没有触摸xmal文件以使代码正常工作。换句话说，我没有在xaml中编写任何代码。我认为大多数开发人员和/或最终用户更喜欢使用DataGrid。
答案 0 :(得分：0)
我看到了一些可以改进此代码的方法。首先，每次单击导航按钮时都不应检索数据。其次，不需要在代码中设置任何控件的Text。它们都绑定到SelectedItem上的ListView。这意味着当您更改ListView的{{1}}时，其值会自动更新。
您应该将数据加载到SelectedItem一次（我假设您在DataTable事件处理程序中执行此操作）。您的导航功能应如下所示：
Loaded从那里，你的private void PreRec_Click(object sender, RoutedEventArgs e)
{
if (ds.Tables[0].Rows.Count > 0)
{
if (rno > 0)
{
rno--;
listView1.SelectedItem = ds.Tables[0].Rows[rno];
}
}
}
将完成所有工作（就像点击Binding中的一行时一样）。
答案 1 :(得分：0)
您的主要问题是，您已将ItemsSource ListView设置为"{Binding}" ...这是绑定到您的整个MainWindow.cs类，而不是数据。为您的数据创建一个属性，然后绑定到该属性，然后您将看到数据。
顺便说一下，ListView不是ComboBox。
答案 2 :(得分：0)
我已在顶部更新了解决方案