Visual Basic

Module Module1

    Sub Main()
        Dim iCount As Integer
        Dim strToSearch As String = "Every instance. Replace() will inteiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiirnally loop throughiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii the entire source string. It replaces all occurrences of the substring you want to replace. Tip: This behavior is useful when dealing with common string replacements in programs.  But: If you do not understand this behavior you may end up writing inefficient code that has unneeded loops. "
        Dim strSearchFor As String = "i"
        Console.WriteLine(strToSearch)
        iCount = strToSearch.Length() - strToSearch.Replace(strSearchFor, "").Length
        Console.WriteLine("There are " + iCount.ToString() + " letter " + strSearchFor + "'s in the string")

    End Sub

End Module

public class StringCharCountBenchmark
{
    private static readonly string _theStringToSearch = "Every instance. Replace() will inteiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiirnally loop throughiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii the entire source string. It replaces all occurrences of the substring you want to replace. Tip: This behavior is useful when dealing with common string replacements in programs.  But: If you do not understand this behavior you may end up writing inefficient code that has unneeded loops. ";
    private static readonly char _theCharToFind = 'i';
    private static readonly string _theCharToFindAsString = "i";

    [Benchmark]
    public int UsingReplace()
    {
        return _theStringToSearch.Length - _theStringToSearch.Replace(_theCharToFindAsString, "").Length;
    }

    [Benchmark]
    public int UsingForEachLoop()
    {
        int result = 0;
        foreach (char c in _theStringToSearch)
        {
            if (c == _theCharToFind)
            {
                result++;
            }
        }

        return result;
    }
    
    [Benchmark]
    public int UsingForLoop()
    {
        int result = 0;
        for (int i = 0; i < _theStringToSearch.Length; i++)
        {
            if (_theStringToSearch[i] == _theCharToFind)
            {
                result++;
            }
        }

        return result;
    }
}

(Yes, I know: C#. But I'm sure you can convert to VB.NET if required. )

// * Summary *

BenchmarkDotNet=v0.11.1, OS=Windows 10.0.17134.228 (1803/April2018Update/Redstone4)
Intel Core i7-4770K CPU 3.50GHz (Haswell), 1 CPU, 8 logical and 4 physical cores
Frequency=3417969 Hz, Resolution=292.5714 ns, Timer=TSC
  [Host]     : .NET Framework 4.7.2 (CLR 4.0.30319.42000), 32bit LegacyJIT-v4.7.3132.0
  DefaultJob : .NET Framework 4.7.2 (CLR 4.0.30319.42000), 32bit LegacyJIT-v4.7.3132.0


           Method |       Mean |     Error |    StdDev |
----------------- |-----------:|----------:|----------:|
     UsingReplace | 3,923.6 ns | 15.267 ns | 12.749 ns |
 UsingForEachLoop |   350.1 ns |  4.453 ns |  3.948 ns |
     UsingForLoop |   376.1 ns |  7.239 ns |  8.046 ns |

Module Module1

    Sub Main()

        Dim strToSearch As String = "john????"
        Dim strSearchFor As String = "?"
        Console.WriteLine(strToSearch)

        Console.WriteLine("There are " + CountOccurrences(strToSearch, strSearchFor).ToString() + " occurrences of " + strSearchFor + " in the string")

    End Sub

    Function CountOccurrences(strStringToSearch As String, strStringToCount As String) As Integer
        Dim iCount As Integer
        iCount = strStringToSearch.Length() - strStringToSearch.Replace(strStringToCount, "").Length
        Return iCount
    End Function

End Module

Dim update1 As String = ("update datamahasiswa set no= @parm1 where nama=@parm2")

Member 12813074 wrote:

(“update datamahasiswa set no= & TextBox1.Text & where nama= & TextBox2.Text & ”)

"update datamahasiswa set no= & TextBox1.Text & where nama= & TextBox2.Text & "

Dim i As Integer
        Dim latihandataset As New latihanDataSet()
        Dim datamahasiswatableadapter As New latihanDataSetTableAdapters.datamahasiswa1TableAdapter
        Try
            Me.Validate()
            Me.LatihanDataSetBindingSource.EndEdit()
            Me.LatihanDataSet.Tables(0).Rows(1).Item(1) = TextBox1.Text
            i = DatamahasiswaTableAdapter1.Update(latihandataset.datamahasiswa)
            Me.DatamahasiswaTableAdapter1.Update(latihandataset.datamahasiswa)
            Me.DatamahasiswaTableAdapter1.Fill(latihandataset.datamahasiswa)
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
        MessageBox.Show("no of rows updated=" & i)