You've got multiple statements in that property, which are not going to process for the Items of the Gallery. You want to return a table.
From the inside out, try this:
Filter (PARAMETROSPRODUCCION; !IsBlank(FECHAINICIO && StartsWith (FECHAINICIO, TextSearchBox1.Text)) -- straight forward; filter the datasource where the field is not blank and where it matches the textbox. Notice that I moved the StartsWith() statement into the logical test of the Filter() statement, using the "&&" operator. This returns a table, so you could have this as the gallery's Item property and it would work fine.
SortByColumns (...filter statement..., "FECHAINICIO", If (SortDescending1, Descending, Ascending)) -- Since you are properly returning a table from your Filter() statement, you can Sort it by your defined column.
The finished product:
SortByColumns ( Filter (PARAMETROSPRODUCCION; !IsBlank(FECHAINICIO && StartsWith (FECHAINICIO, TextSearchBox1.Text)), "FECHAINICIO", If (SortDescending1, Descending, Ascending) )
Hopefully this translates well enough. Post back if you still have problems.
Some funny spaces crept into that code block. Let me try again. If this still throws an error, post what the error says and where it is located in the formula.
SortByColumns ( Filter (PARAMETERSPRODUCTION; !IsBlank(STARTFLEX) && StartsWith (STARTFLEX, TextSearchBox1.Text)), "START DATE", If (SortDescending1, Descending, Ascending) )
Also make sure that the field names match your datasource. Dealing with automatic translation, they might have been changed. Specifically, check that your datasource is named PARAMETERPRODUCTION, and that it has fields named STARTFLEX and "Start Date".
Easiest thing, given the language difference and not knowing the exact layout of your data, would be for you to try the following:
Reduce the Items property to just the Filter() statement. Maybe even remove the StartsWith() part. Just filter for where the field is blank. See if that works. If it does, add the StartsWith() back in. The syntax looks correct. I have to think it is something in how you are referencing your data.
If just the Filter() statement produces an error, hover over the red line and report the message it is giving you.
No, you still have the SortByColumns() in there, too. Set it to be just:
I have run a test on my end, and that should work. If it doesn't, hover over the red lines (like what are in your image), and report what the error is.