Clear the contents of multiple TextBox objects in WPF

Question

I have following XAML in WPF

<Canvas>
    <WrapPanel x:Name="TimeTableMainWrapPanel" Canvas.Left="109" Canvas.Top="195" Height="601" Width="745>
        <TextBox x:Name="txtFirstLctrTime"  Height="24" TextWrapping="Wrap" Width="115"/>
        <TextBox x:Name="txtSecondLctrTime" Height="23" Canvas.Left="594" TextWrapping="Wrap" Canvas.Top="189" Width="115"/>

        <WrapPanel x:Name="TimeTableSubWrapPanel" Canvas.Left="109" Canvas.Top="195" Height="601" Width="745">
            <WrapPanel x:Name="FirstLecture" Background="#00F0F8FF" Height="392" Width="133" Margin="0,0,10,0">
                <TextBox x:Name="txtMondayFirstLctr" Width="133" Margin="0" Height="30" FontSize="13" VerticalContentAlignment="Center"/>
                <TextBox x:Name="txtTuesdayFirstLctr" Width="133" Margin="0,38,0,0" Height="30" FontSize="13" VerticalContentAlignment="Center"/>
            </WrapPanel>

            <WrapPanel x:Name="SecondLecture" Canvas.Top="220" Background="#00F0F8FF" Canvas.Left="270" Height="466" Width="133" Margin="8,0,10,0">
                <TextBox x:Name="txtMondaySecondLctr" Width="133" Margin="0,38,0,0" Height="30" VerticalContentAlignment="Center"></TextBox>
                <TextBox x:Name="txtTuesdaySecondLctr" Width="133" Margin="0,38,0,0" Height="30" VerticalContentAlignment="Center"></TextBox>
            </WrapPanel>
        </WrapPanel>
    </WrapPanel>
</Canvas>

I wanted to clear content of all textbox on button click. And for that I am doing

var firsttextboxes = this.FirstLecture.Children.OfType<TextBox>();
var secondtextboxes = this.SecondLecture.Children.OfType<TextBox>();

foreach (var textbox in firsttextboxes)
{
    textbox.Clear();
}

foreach (var textbox in secondtextboxes)
{
    textbox.Clear();
}

Is there any better way of doing this, instead of using multiple foreach loops?

Also how do I enter one value in each TextBox and move to next?

I am trying the code below, but it is inserting the same value in all TextBox objects:

foreach(var a in firsttextboxes ) 
{ 
    foreach(var b in Text) 
    { 
        a.Text = b 
    } 
}

score 1 · Accepted Answer · answered Apr 06 '15 at 10:02

1

Use Union and combine all the sources. Then foreach over allTextboxes.

var allTextboxes = firsttextboxes
                    .Union(secondtextboxes)
                    .Union(thirdtextboxes);
                    //And so on
foreach (var textbox in allTextboxes )
{
    textbox.Clear();
}

Another approach would be looking at the visual tree to find out all the TextBoxes within the parent WrapPanel and clear them.

answered Apr 06 '15 at 10:02

Sriram Sakthivel

72,067
7
111
189

One last ques, if i have Five textbox and five values how will i append one value each in respective Textbox using foreach? I trie like foreach(var a in Timetable) { foreach(var b in Text) { a.Text = b } } BUt it is inserting same value in all Textbox – Richa Apr 06 '15 at 10:10
1

@Richa You're doing it wrong. If you do this way, it will be a maintenance problem for you. Please look at `DataBinding`. Create a ViewModel class which exposes (those 5)properties and bind respective property to the `TextBox`. Then implement `INotifyPropertyChanged` interface in ViewModel, so that when the property is updated, TextBox will be automatically updated. Search for "Wpf Mvvm databinding" – Sriram Sakthivel Apr 06 '15 at 10:16

Vimal CK · Answer 2 · 2015-04-06T10:44:09.667

1

I have created a Generic method to do the same. PerformOperationOnVisualTreeControl method accepts parent control and an `Action method to define your operation.

public static void PerformOperationOnVisualTreeControl<T>(Visual myVisual, Action<T> action)
{
        for (int i = 0; i < VisualTreeHelper.GetChildrenCount(myVisual); i++)
        {
            var childVisual = (Visual)VisualTreeHelper.GetChild(myVisual, i);
            if (typeof(T) == childVisual.GetType())
            {
                T control = (T)System.Convert.ChangeType(childVisual, typeof(T));
                action(control);
            }

            PerformOperationOnVisualTreeControl<T>(childVisual, action);
        }
}

You can call PerformOperationOnVisualTreeControl method like below

Update : I have created a Queue to update all the TextBox with database values. Queue will Dequeue value one by one and update the TextBox

var dbValues = new Queue<int>(Enumerable.Range(1, 5));
PerformOperationOnVisualTreeControl<TextBox>(this.TimeTableSubWrapPanel, (control) =>
{
    control.Clear();
    if (dbValues.Count > 0)
    {
        control.Text = dbValues.Dequeue().ToString();
    }
});

edited Apr 06 '15 at 10:44

answered Apr 06 '15 at 10:27

Vimal CK

3,543
1
26
47

@Richa sorry it was a typo, i have updated the answer, – Vimal CK Apr 06 '15 at 10:32
Works good. Thanks A lot . Can you help in second part of question? – Richa Apr 06 '15 at 10:32
you can pass any action which you want to perform on a particular control. – Vimal CK Apr 06 '15 at 10:33
Can you explain more what you want achieve in the 2nd part – Vimal CK Apr 06 '15 at 10:35
If i have 5 textbox and i fetch 5 number from DB, i want to append first value in first textbox and so on . So say i have 5 value fetched from Db 1,2,3,4,5 so first texbox should have value 1,second texbox value 2 and s on – Richa Apr 06 '15 at 10:36
What issue are you getting, Please explain – Vimal CK Apr 06 '15 at 10:57
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/74554/discussion-between-richa-and-vimal-ck). – Richa Apr 06 '15 at 10:57

score 0 · Answer 3 · answered Apr 06 '15 at 10:13

void ClearDescendantTextBoxes(Control ctrl)
{
    foreach (Control child in ctrl.Controls)
        if (child is TextBox)
            child.Text = "";
        else ClearDescendantTextBoxes(child);
}

(This is for winforms. But you can probably fix it easily for wpf.)

score 0 · Answer 4 · answered Apr 07 '15 at 12:50

In regards to MVVM, I would Create a command for the button that is responsible for clearing the textboxes.

I would then implement the command by setting the observable properties that should be bound to the textboxes to null.

This removes the code-behind that typically grows into a maintenance nightmare / God-class.

score 0 · Answer 5 · answered Mar 24 '21 at 14:46

0

var allTextboxes = this.mainpan.Children.OfType();

        foreach (var textbox in allTextboxes)
        {
            textbox.Clear();
        }
        var allTextboxe = this.mainpan.Children.OfType<ComboBox>();
        foreach (var textbox in allTextboxe)
        {
            textbox.SelectedIndex = 0;
        }

answered Mar 24 '21 at 14:46

maher babar

1
4

1

This answer could be better explained, especially since this answer is 5+ years later than the original question. Does it add anything that the other answers did not? Please elaborate if possible so that anyone who comes across this in the future will have more context. – Tori Henri Mar 24 '21 at 21:38

Clear the contents of multiple TextBox objects in WPF

5 Answers5