The form has a text field and a datagridview. It is necessary, without displaying the entire contents of the json file in the DataGridView, to search for the json file and display the search result in the DataGridView.You need to search by the UserName tag. You need to start typing either the first or last name in the text field and in the datagridview display the result of the found

How to read text file in dataGridView I know:

Imports System.IO
Imports Newtonsoft.Json

Public Class Form1

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    End Sub
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim result = JsonConvert.DeserializeObject(Of List(Of Users))(File.ReadAllText("D:\Users.json"))
        DataGridView1.DataSource = result
    End Sub

      Public Class Users
        Public Property ID() As Integer
        Public Property UserName() As String
        Public Property Login() As String
        Public Property Title() As String
        Public Property Dep() As String
        Public Property Mail() As String
        Public Property Phone() As String
    End Class

End Class

I also know how to do a file search. Only for some reason the result displays – the first element found:

  Dim json As String = File.ReadAllText("D:\Users.json")
        Dim objectList = JsonConvert.DeserializeObject(Of List(Of Users))(json)
        Dim foundItem = objectList.Where(Function(underscore) underscore.UserName.Contains("Tom")).FirstOrDefault()

        If foundItem IsNot Nothing Then
            MessageBox.Show(foundItem.UserName)

        Else
            MsgBox("none")
        End If

And the actual contents of the json file itself:

[
{
"id":"1",
"UserName":"Fred Smith",
"Login":"f.smith",
"Title":"engineer",
"Dep":"IT infrastcomcture",
"Mail":"[email protected]",
"Phone":"111",
},
{
"id":"2",
"UserName":"Ben Taylor",
"Login":"b.taylor",
"Title":"programmer",
"Dep":"IT infrastcomcture",
"Mail":"[email protected]",
"Phone":"100",
},
{
"id":"3",
"UserName":"Steve Harris",
"Login":"s.harris",
"Title":"System Administrator",
"Dep":"IT infrastcomcture",
"Mail":"[email protected]",
"Phone":"263",
},
{
"id":"4",
"UserName":"Tom Walker",
"Login":"t.walker",
"Title":"engineer",
"Dep":"IT infrastcomcture",
"Mail":"[email protected]",
"Phone":"263",
},
{
"id":"5",
"UserName":"Tom Davis",
"Login":"t.davis",
"Title":"engineer",
"Dep":"IT infrastcomcture",
"Mail":"[email protected]",
"Phone":"200",
},
{
"id":"6",
"UserName":"Ben Walker",
"Login":"b.walker",
"Title":"System Administrator",
"Dep":"IT infrastcomcture",
"Mail":"[email protected]",
"Phone":"167",
},
]