How build dynamic where clause with string argument - vb.net

Question

I try to buid a method to add a where clause to a Linq-to-SQL request (return an IQueryable). I try several methods but always use ToString, Indexof... but this result is a sql request take all element and the filter made in linq. I see request in SQL Server profiler.
I want a method to do it with result is a sql request with where include inside
I work in Visual Studio 2017 with SQL Server 2016. I code in vb.net
I see an interesting thing in linq dynamic library. But I can't to adapt to my situation
<Extension()> _
Public Function Where(ByVal source As IQueryable, ByVal predicate As String, ByVal ParamArray values() As Object) As IQueryable
If source Is Nothing Then Throw New ArgumentNullException("source")
If predicate Is Nothing Then Throw New ArgumentNullException("predicate")
Dim lambda As LambdaExpression = DynamicExpression.ParseLambda(source.ElementType, GetType(Boolean), predicate, values)
Return source.Provider.CreateQuery( _
Expression.Call( _
GetType(Queryable), "Where", _
New Type() {source.ElementType}, _
source.Expression, Expression.Quote(lambda)))
End Function
But I don't need all this complex strucutre. It's some years I buid my utilities. But Need to upgrade it. Here my code of my utilities
<Extension()>
Public Function Where(ByVal source As IQueryable, ByVal predicate As String) As IQueryable
Dim param = Expression.Parameter(GetType(String), "x")
Return source.Provider.CreateQuery(
Expression.Call(
GetType(Queryable), "Where",
New Type() {source.ElementType},
source.Expression, Expression.Quote(Expression.Lambda(Expression.Constant(predicate), param))))
End Function
Public Function TFOAppliqueFiltreTri(Of T, MaClassDatas As Class)(Origins As IQueryable(Of T), ByVal MesDonnees As TableFullOption.PagerTabEnCours(Of MaClassDatas)) As IQueryable(of T)
Dim retour As New TableFullOption.LstRetour
'Colonne de filtre
Dim strWh As String = ""
Dim Filtredrecords As IQueryable(Of T)
For Each Sort In MesDonnees.MesOptions
Dim colName = Sort.ColName
If strWh.Length > 0 Then strWh = strWh & " AND "
strWh = strWh & String.Format(colName & " like '%{0}%'", Sort.Search)
Next
If strWh.Length > 0 Then
Filtredrecords = Origins.Where(strWh) '<- Here call Where
Else
Filtredrecords = Origins
End If
Return Filtredrecords
End Function
I get this error:
Aucune méthode générique 'Where' sur le type 'System.Linq.Queryable' n'est compatible avec les arguments de type et les arguments fournis..
Then my problem is to write correctly lambda expression. My predicate argument is : Column1 like '%aaa%'. I want rewrite where method of dynamicLinq to accept string argument :Column1 like '%aaa%' directly
Thanks for your help

Answer 1

Finally after lot of reading in google and few feelings and certainly lot of chance.
Public Function Where(Of TEntity)(source As IQueryable(Of TEntity), searchColumn As List(Of String), searchValue As String) As IQueryable(Of TEntity)
Dim cond As Expression = Nothing
Dim ParamExpr = Expression.Parameter(GetType(TEntity), "x")
Dim conCat2 = GetType(String).GetMethod("Concat", New Type() {GetType(String), GetType(String)})
Dim conCat4 = GetType(String).GetMethod("Concat", New Type() {GetType(String), GetType(String), GetType(String), GetType(String)})
Dim Delim = Expression.Constant("/")
Dim DateName = GetType(SqlFunctions).GetMethod("DateName", New Type() {GetType(String), GetType(Nullable(Of DateTime))})
Dim DatePart = GetType(SqlFunctions).GetMethod("DatePart", New Type() {GetType(String), GetType(Nullable(Of DateTime))})
Dim DblToString = GetType(SqlFunctions).GetMethod("StringConvert", New Type() {GetType(Nullable(Of Double))})
For Each cn In searchColumn
For Each colName In cn.Split("|")
If Not colName.estVide Then
Dim body As Expression = ParamExpr
For Each member In colName.Split(".")
body = Expression.PropertyOrField(body, member)
Next
Dim Tostr As Expression
If body.Type.FullName.Contains("String") Then
Tostr = body
ElseIf body.Type.FullName.Contains("DateTime") Then
Dim day = Expression.Call(Expression.Call(conCat2, Expression.Constant("0"), Expression.Call(DateName, Expression.Constant("day"), body)), "Substring", Nothing, Expression.Constant(0), Expression.Constant(2))
Dim Month = Expression.Call(DatePart, Expression.Constant("MM"), body)
Dim toDouble = Expression.Convert(Month, GetType(Nullable(Of Double)))
Dim mois = Expression.Call(conCat2, Expression.Constant("0"), Expression.Call(Expression.Call(DblToString, toDouble), "Trim", Nothing))
Dim an = Expression.Call(DateName, Expression.Constant("year"), body)
Tostr = Expression.Call(conCat2, Expression.Call(conCat4, day, Delim, mois, Delim), an)
Else
Tostr = Expression.Call(body, "Convert.ToString", Nothing)
'Tostr = Expression.Convert(body, GetType(String))
End If
Dim condPart = Expression.Call(Expression.Call(Tostr, "ToLower", Nothing), "Contains", Nothing, Expression.Call(Expression.Constant(searchValue), "ToLower", Nothing))
If cond Is Nothing Then
cond = condPart
Else
cond = Expression.OrElse(cond, condPart)
End If
End If
Next
Next
Return source.Provider.CreateQuery(Of TEntity)(Expression.Call(GetType(Queryable), "Where", New Type() {GetType(TEntity)}, source.Expression, Expression.Lambda(cond, ParamExpr)))
End Function
Now I've dynamic filter which generated a SQL request with complete clause where