DataGrid : Workaround for DatePicker being set to null no matter what when filter is set through Parameter FilterSearchValue

Source/Extensions/Blazorise.DataGrid/DataGrid.razor

@@ -181,7 +181,7 @@
                                     }
                                     else
                                     {
-                                        <_DataGridCellFilter Column="column" FilterSearchValue="@column.Filter.SearchValue" OnFilterChanged="@((newValue) => OnFilterChanged(column, newValue))" />
+                                        <_DataGridCellFilter Column="column" OnFilterChanged="@((newValue) => OnFilterChanged(column, newValue))" />
                                     }
                                 </TableHeaderCell>
                             }

Source/Extensions/Blazorise.DataGrid/Enums/DataGridCellFilterType.cs

@@ -0,0 +1,22 @@
+namespace Blazorise.DataGrid;
+
+/// <summary>
+/// Defines the DataGrid cell filter type.
+/// </summary>
+public enum DataGridCellFilterType
+{
+    /// <summary>
+    /// Represents a single filter, allowing only one value.
+    /// </summary>
+    Single,
+
+    /// <summary>
+    /// Represents the starting value of a range filter.
+    /// </summary>
+    RangeFrom,
+
+    /// <summary>
+    /// Represents the ending value of a range filter.
+    /// </summary>
+    RangeTo,
+}

Source/Extensions/Blazorise.DataGrid/_DataGridCellFilter.razor

@@ -3,33 +3,86 @@
 @{
     if ( Column is DataGridNumericColumn<TItem> numericColumn )
     {
-        <_DataGridCellNumericEdit Column="@numericColumn" CellValue="@FilterSearchValue" CellValueChanged="@OnFilterChanged"></_DataGridCellNumericEdit>
+        <_DataGridCellNumericEdit Column="@numericColumn" CellValue="@GetSearchValue()" CellValueChanged="@FilterChanged"></_DataGridCellNumericEdit>
 
     }
     else if ( Column is DataGridSelectColumn<TItem> selectColumn )
     {
-        <_DataGridCellSelectEdit Column="@selectColumn" CellValue="@FilterSearchValue" CellValueChanged="@OnFilterChanged"></_DataGridCellSelectEdit>
+        <_DataGridCellSelectEdit Column="@selectColumn" CellValue="@GetSearchValue()" CellValueChanged="@FilterChanged"></_DataGridCellSelectEdit>
 
     }
     else if ( Column is DataGridCheckColumn<TItem> checkColumn )
     {
-        <_DataGridCellCheckEdit Column="@checkColumn" CellValue="@FilterSearchValue" CellValueChanged="@OnFilterChanged"></_DataGridCellCheckEdit>
+        <_DataGridCellCheckEdit Column="@checkColumn" CellValue="@GetSearchValue()" CellValueChanged="@FilterChanged"></_DataGridCellCheckEdit>
 
     }
     else if ( Column is DataGridDateColumn<TItem> dateColumn )
     {
-        <_DataGridCellDatePicker Column="@dateColumn" CellValue="@FilterSearchValue" CellValueChanged="@OnFilterChanged"></_DataGridCellDatePicker>
+        <_DataGridCellDatePicker Column="@dateColumn" CellValue="@GetSearchValue()" CellValueChanged="@FilterChanged"></_DataGridCellDatePicker>
 
     }
     else
     {
-        <TextEdit Text="@FilterSearchValue?.ToString()" TextChanged="@((value) => OnFilterChanged.InvokeAsync(value))" />
+        <TextEdit Text="@GetSearchValueAsString()" TextChanged="@((newValue) => FilterChanged(newValue))" />
     }
 }
 @code {
     [Parameter] public DataGridColumn<TItem> Column { get; set; }
 
     [Parameter] public EventCallback<object> OnFilterChanged { get; set; }
 
-    [Parameter] public object FilterSearchValue { get; set; }
+    /// <summary>
+    /// Workaround for an issue with the DatePicker setting the value to null if we try to set FilterValue as a Parameter.
+    /// </summary>
+    [Parameter] public DataGridCellFilterType CellFilterType { get; set; } = DataGridCellFilterType.Single;
+
+    private Task FilterChanged( object newValue )
+    {
+        return OnFilterChanged.InvokeAsync( newValue );
+    }
+
+    private string GetSearchValueAsString()
+    {
+        if ( CellFilterType == DataGridCellFilterType.Single )
+        {
+            return Column.Filter.SearchValue?.ToString();
+        }
+        else if ( CellFilterType == DataGridCellFilterType.RangeFrom )
+        {
+            return GetFilterValue1()?.ToString();
+        }
+        else if ( CellFilterType == DataGridCellFilterType.RangeTo )
+        {
+            return GetFilterValue2()?.ToString();
+        }
+        return default;
+    }
+
+    private object GetSearchValue()
+    {
+        if ( CellFilterType == DataGridCellFilterType.Single )
+        {
+            return Column.Filter.SearchValue;
+        }
+        else if ( CellFilterType == DataGridCellFilterType.RangeFrom )
+        {
+            return GetFilterValue1();
+        }
+        else if ( CellFilterType == DataGridCellFilterType.RangeTo )
+        {
+            return GetFilterValue2();
+        }
+        return default;
+    }
+
+    private object GetFilterValue1()
+    {
+        return ( Column.Filter.SearchValue as object[] )?[0];
+    }
+
+    private object GetFilterValue2()
+    {
+        return ( Column.Filter.SearchValue as object[] )?[1];
+    }
+
 }

Source/Extensions/Blazorise.DataGrid/_DataGridMenuFilter.razor

@@ -45,12 +45,12 @@
                     <Field @key=filterMethod>
                         @if ( filterMethod == DataGridColumnFilterMethod.Between )
                         {
-                            <_DataGridCellFilter Column="Column" FilterSearchValue="@GetFilterValue1()" OnFilterChanged="@SetFilterValue1" />
-                            <_DataGridCellFilter Column="Column" FilterSearchValue="@GetFilterValue2()" OnFilterChanged="@SetFilterValue2" />
+                            <_DataGridCellFilter Column="Column" CellFilterType="DataGridCellFilterType.RangeFrom" OnFilterChanged="@SetFilterValue1" />
+                            <_DataGridCellFilter Column="Column" CellFilterType="DataGridCellFilterType.RangeTo" OnFilterChanged="@SetFilterValue2" />
                         }
                         else
                         {
-                            <_DataGridCellFilter Column="Column" FilterSearchValue="Column.Filter.SearchValue" OnFilterChanged="@((newValue) => Column.Filter.SearchValue = newValue)" />
+                            <_DataGridCellFilter Column="Column" OnFilterChanged="@((newValue) => Column.Filter.SearchValue = newValue)" />
                         }
                     </Field>
                 </Column>