using excel range find return Type mismatch. (Exception from HRESULT: 0x80020005 (DISP_E_TYPEMISMATCH))

I'm working on Excel add-on I need to search Values on cell (selected by user) in Column (Selected by user) and write result in cell (selected by user)

Ex: if cell A2 exist in column B in rows 5, 10, and 15 result in C2 must be 5,10,15

I Face error when trying to find Row using this code

result = sheetName.Cells.Find(cellVal, SearchRange, Excel.XlFindLookIn.xlValues, Excel.XlLookAt.xlWhole, _
                                       Excel.XlSearchOrder.xlByRows, Excel.XlSearchDirection.xlNext, _
                                       Type.Missing, Type.Missing, Type.Missing).Row.ToString

and with this code too

    result = sheetName.Cells.Find(What:=cellVal, LookIn:=SearchRange.Value, SearchOrder:=SearchRange.Rows, _
                  SearchDirection:=Excel.XlSearchDirection.xlNext, MatchCase:=False, SearchFormat:=False).ToString

My Full Code here

Dim xlapp As Excel.Application = Globals.ThisAddIn.Application
Dim sheetName As Excel.Worksheet
sheetName = Globals.ThisAddIn.Application.ActiveSheet

Dim LastDataRow As Integer = sheetName.Range(cmbCheckDataCol.Text & sheetName.Rows.Count).End(Excel.XlDirection.xlUp).Row
Dim LastCheckInRow As Integer = sheetName.Range(cmbCheckRngCol.Text & sheetName.Rows.Count).End(Excel.XlDirection.xlUp).Row
Dim SearchRange As Excel.Range = sheetName.Range(cmbCheckRngCol.Text & "2", cmbCheckRngCol.Text & LastCheckInRow.ToString)
' --------------------------------- start check
Dim cellVal, result As String
For rowNum As Integer = 2 To LastDataRow

    cellVal = sheetName.Range(cmbCheckDataCol.Text & rowNum.ToString).Value.ToString   ' if null will return Error
    'result = xlapp.WorksheetFunction.CountIf(SearchRange, cellVal)                  ' search
    result = sheetName.Cells.Find(cellVal, SearchRange, Excel.XlFindLookIn.xlValues, Excel.XlLookAt.xlWhole, _
                               Excel.XlSearchOrder.xlByRows, Excel.XlSearchDirection.xlNext, _
                               Type.Missing, Type.Missing, Type.Missing).Row.ToString

I get error Type mismatch. (Exception from HRESULT: 0x80020005 (DISP_E_TYPEMISMATCH)) when trying to assign row number to result variable

I Temporary changed my code to below code and it works with me

   Dim LastDataRow As Integer = sheetName.Range(cmbCheckDataCol.Text & sheetName.Rows.Count).End(Excel.XlDirection.xlUp).Row
    Dim LastCheckInRow As Integer = sheetName.Range(cmbCheckRngCol.Text & sheetName.Rows.Count).End(Excel.XlDirection.xlUp).Row
    Dim SearchRange As Excel.Range = sheetName.Range(cmbCheckRngCol.Text & "2", cmbCheckRngCol.Text & LastCheckInRow.ToString)
    ' --------------------------------- start check
    Dim cellVal As String = ""
    Dim result As String = "In Row"
    Dim Curentfind As Excel.Range = Nothing
    Dim FirstFind As Excel.Range = Nothing       ' for try microsoft
    For rowNum As Integer = 2 To LastDataRow
        ' ---- try microsoft
        Try
            cellVal = sheetName.Range(cmbCheckDataCol.Text & rowNum.ToString).Value.ToString   ' if null will return Error
            Dim ifExist As Long = xlapp.WorksheetFunction.CountIf(SearchRange, cellVal)
            If ifExist > 0 Then      ' start get rows
                Curentfind = SearchRange.Find(cellVal, , _
                              Excel.XlFindLookIn.xlValues, Excel.XlLookAt.xlPart, _
                              Excel.XlSearchOrder.xlByRows, Excel.XlSearchDirection.xlNext, False)
                Dim fFind As String = Curentfind.Address.ToString       ' record find first address to avoid infiniti loop
                For ce As Integer = 1 To LastCheckInRow
                    result &= ", " & Curentfind.Address.ToString.ToUpper
                    Curentfind = SearchRange.FindNext(Curentfind)
                    If Curentfind.Address.ToString = fFind Then Exit For ' breakloop , find back to first address
                Next
                result = Replace(result, "$", "")
            Else
                result = "Not Exist"
            End If

        Catch ex As Exception
            result = "Error, No data in Cell " & cmbCheckDataCol.Text.ToUpper & rowNum.ToString
        End Try
        ' write result
        sheetName.Range(cmbCheckResltCol.Text & rowNum.ToString).Value = result
        result = "In Row"


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