How to get the value of textbox in ViewModel in WPF - MVVM
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Hi guys, I'm working for the first time in WPF with MVVM pattern and I have a datagrid that is populated according to search terms in textbox on top. Right now, I'm able to populate the grid with all the data but I'm not able to get the value of the TextBox so I can filter it. So here's a bit of the code: In ViewModel:
private string p_searchName;
public string _searchName
{
get
{
return p_searchName;
}
set
{
p_searchName = value;base.RaisePropertyChanged("\_searchName"); } }In xaml file
Any help is greatly appreciated! Thanks
Rocky My Blog
The binding looks right, but are there any errors in the output window when loading that form? The other thing that it may be, is that the TextBox control doesn't update the ViewModel until it loses focus. Not sure about that though...
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Hi guys, I'm working for the first time in WPF with MVVM pattern and I have a datagrid that is populated according to search terms in textbox on top. Right now, I'm able to populate the grid with all the data but I'm not able to get the value of the TextBox so I can filter it. So here's a bit of the code: In ViewModel:
private string p_searchName;
public string _searchName
{
get
{
return p_searchName;
}
set
{
p_searchName = value;base.RaisePropertyChanged("\_searchName"); } }In xaml file
Any help is greatly appreciated! Thanks
Rocky My Blog
Make your binding
Mode="TwoWay"default is only one way so you see the data but are not telling the datacontext the data has changed And yes the change is only notified when the user leaves the textboxNever underestimate the power of human stupidity RAH
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Make your binding
Mode="TwoWay"default is only one way so you see the data but are not telling the datacontext the data has changed And yes the change is only notified when the user leaves the textboxNever underestimate the power of human stupidity RAH
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You need to set your UpdateSourceTrigger in your binding like this
<TextBox Text="{Binding MyProperty, UpdateSourceTrigger=PropertyChanged}"/>*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington
"Mind bleach! Send me mind bleach!" - Nagy Vilmos
CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier
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The binding looks right, but are there any errors in the output window when loading that form? The other thing that it may be, is that the TextBox control doesn't update the ViewModel until it loses focus. Not sure about that though...
There are no errors in the output window. But you are quite right about the focus. I just added
UpdateSourceTrigger=PropertyChanged
like this
<TextBox Text="{Binding Name, UpdateSourceTrigger=PropertyChanged}"/>
and it actually works... But I really don't see why this is so. Thanks for the help!
Rocky My Blog
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You need to set your UpdateSourceTrigger in your binding like this
<TextBox Text="{Binding MyProperty, UpdateSourceTrigger=PropertyChanged}"/>*pre-emptive celebratory nipple tassle jiggle* - Sean Ewington
"Mind bleach! Send me mind bleach!" - Nagy Vilmos
CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier
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Yes you're right. Just did that a minute ago or so :) By the way... do you know why this is so? Just curious!
Rocky My Blog
The WPF textbox has a default UpdateSourceTrigger of LostFocus, which means that it only updates it's bound value when the user focuses on another control. By changing the trigger to update when the property changes, it updates it's bound value every time the user enters/deletes/changes a letter. Here is the MSDN page that discusses this How to: Control when the TextBox Text Updates the Source[^] . Hope this helps
When I was a coder, we worked on algorithms. Today, we memorize APIs for countless libraries — those libraries have the algorithms - Eric Allman
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There are no errors in the output window. But you are quite right about the focus. I just added
UpdateSourceTrigger=PropertyChanged
like this
<TextBox Text="{Binding Name, UpdateSourceTrigger=PropertyChanged}"/>
and it actually works... But I really don't see why this is so. Thanks for the help!
Rocky My Blog
I assume the default for UpdateSourceTrigger is LostFocus, and it is set that way for performance reasons. Every time you call the setter, the setter raises the OnPropertyChanged event, WPF listens to that event and calls the getter.
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The WPF textbox has a default UpdateSourceTrigger of LostFocus, which means that it only updates it's bound value when the user focuses on another control. By changing the trigger to update when the property changes, it updates it's bound value every time the user enters/deletes/changes a letter. Here is the MSDN page that discusses this How to: Control when the TextBox Text Updates the Source[^] . Hope this helps
When I was a coder, we worked on algorithms. Today, we memorize APIs for countless libraries — those libraries have the algorithms - Eric Allman
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I assume the default for UpdateSourceTrigger is LostFocus, and it is set that way for performance reasons. Every time you call the setter, the setter raises the OnPropertyChanged event, WPF listens to that event and calls the getter.
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Great, Glad it helped :)
When I was a coder, we worked on algorithms. Today, we memorize APIs for countless libraries — those libraries have the algorithms - Eric Allman