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public void Set_filter(Int32 Nummer, string Column, string Filter)
        {
            BindingSource Grid_Source = new BindingSource();
            DataGridView Grid = new DataGridView();
            if (Nummer == 1)
            {
                Grid_Source = Grid1_Source;
                Grid = dataGridView1;
            }
            else if (Nummer == 2)
            {
                Grid_Source = Grid2_Source;
                Grid = dataGridView2;
            }
            else if (Nummer == 3)
            {
                Grid_Source = Grid3_Source;
                Grid = dataGridView3;
            }
            else if (Nummer == 4)
            {
                Grid_Source = Grid4_Source;
                Grid = dataGridView4;
            }
         
            Grid_Source.Filter = String.Format(Column + " LIKE '%" + Filter +"%'");
            Grid.DataSource = Grid_Source;
            Grid.Refresh();

        }                    

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Grid_Source.Filter = String.Format(Column + " LIKE '%" + Filter +"%'");