Populate a text box indexed from a listbox selection

[Codmental]

Hello, I hope that you can help me. Firstly, I think that Radzen is an amazing tool and have got a fully working CRUD example based on my SQL DB with very little effort. I now need to progress the App by adding functionality and I admit that most of my issues are due to very poor C# skills. I am on a very steep learning curve here!

I have tried for what seems like days to do what should be a very simple thing. I have a dropdown list created as part of my SQL Scaffolding (Foreign Field on Species_ID both tables) which I have set-up to pull a list from a SQL table - [SpeciesList]. The edit form is for adding new entries to another table (model) for [SpeciesSightingRecord] two values of which are being picked up from the Species list. This works well and I can select [BinomialName] from the drop down list and have it saved back to the DB. However, there is a second field [CommonName] that is from the same SQL result (row) and I want to have a text box on the form updated based on the list selection. So, pick a Binomial Name from the list box and if a Common Name exists in the same row, have it populate a text box, I have tried numerous examples based on other requests on the forum but cannot get it to work. I tried following your example (orderdetail.Product = getProductsResult.FirstOrDefault(p => p.ProductID == ${event})) by modifying to suit but I keep getting implicit conversion errors and all sorts of other things depending on what I have tried. Seems like the OnChange args are not compatible with what I am trying to do = e.g. String to int etc... Any chance that you could explain the best way to do this. Maybe, as it is only two tables, the solution is more straight forward? I was hoping to learn by doing but have reached a total dead end. This would be much appreciated as I am a volunteer at a charity trying to 'help out' with an old legacy Access database that needs bringing into the 21st Century! I have the SQL knowledge but am not a web / C# programmer. Many thanks...

[korchev]

Hi @Codmental,

@Codmental

I want to have a text box on the form updated based on the list selection

You need to set the Value property of the TextBox to some expression which depends on the Value of the DropDownList. More info is available in the documentation: Properties (Blazor)
Expressions (Blazor)
The Value of the TextBox should be a string property.

@Codmental

I have tried numerous examples based on other requests on the forum but cannot get it to work

What did you try and how did it fail?

@Codmental

I tried following your example (orderdetail.Product = getProductsResult.FirstOrDefault(p => p.ProductID == ${event})) by modifying to suit but I keep getting implicit conversion errors and all sorts of other things depending on what I have tried.

What example are you referring to? What is the actual compiler error?

@Codmental

So, pick a Binomial Name from the list box and if a Common Name exists in the same row, have it populate a text box,

I don't understand this requirement.

[Codmental]

Hi, thanks for the reply. I have played around some more and it turns out that what actually I needed was two dropdown data grids, both linked to the same Data source (by ID) but with different column names. This then works ‘out of the box’.

Now, if I select from one list, the other one automatically updates with the corresponding item. This is exactly what I wanted except that previously I had one as a Dropdown list and the other as a text box. I don’t know why I didn’t get there sooner, but it is all a learning curve for me.

I will now inspect the Blazor code to see what was done there and hopefully it will make sense!

Thanks for your help...