ReoGrid provides cell-level and worksheet-level protection to prevent users from modifying data. This includes locking individual cells, locking the entire worksheet, and making the workbook read-only.

Cell-Level Locking

Each cell has an IsLocked property of type CellLock that controls whether the cell can be edited.

CellLock Enum

Lock Individual Cells

// Lock a specific cell
sheet.Cells["A1"].IsLocked = CellLock.Locked;

// Unlock a specific cell
sheet.Cells["B2"].IsLocked = CellLock.Unlocked;

// Reset to inherit from worksheet
sheet.Cells["A1"].IsLocked = CellLock.Inherit;

Lock a Range of Cells

To lock multiple cells, iterate over them:

sheet.IterateCells("A1:D10", (row, col, cell) =>
{
    if (cell != null) cell.IsLocked = CellLock.Locked;
    return true; // continue iteration
});

Cell ReadOnly Property

Individual cells also have a IsReadOnly property for a simpler read-only flag:

sheet.Cells["A1"].IsReadOnly = true;

Note: When a locked cell is being edited, setting IsLocked to Locked immediately ends the edit session. If AlwaysMoveSelectionToUnlockedCell is enabled, the selection also moves to the nearest unlocked cell.

Worksheet-Level Locking

Lock or unlock the entire worksheet:

// Lock the entire worksheet
sheet.IsLocked = true;

// Unlock the entire worksheet
sheet.IsLocked = false;

When a worksheet is locked:

• Cells with IsLocked = CellLock.Inherit become locked
• Cells with IsLocked = CellLock.Unlocked remain editable
• Any active edit session is ended immediately

Selectable Locked Cells

By default, locked cells can still be selected. To prevent selection of locked cells:

sheet.IsLockedCellSelectable = false;

Move Selection to Unlocked Cell

Programmatically move the selection to the nearest unlocked cell:

sheet.MoveSelectionRangeToUnlockedCell();

Auto-Move to Unlocked Cell

Automatically move selection to unlocked cells when the worksheet is locked:

sheet.Options.AlwaysMoveSelectionToUnlockedCell = true;

Workbook-Level Read-Only

Set the entire workbook (all worksheets) to read-only mode:

// Make the entire workbook read-only
reoGridControl.Readonly = true;

// Make it writable again
reoGridControl.Readonly = false;

This sets the Edit_Readonly worksheet setting on all worksheets.

Worksheet Read-Only Setting

Use the worksheet settings to make individual worksheets read-only:

// Make a single worksheet read-only
sheet.SetSettings(WorksheetSettings.Edit_Readonly, true);

// Check if read-only
bool isReadonly = sheet.HasSettings(WorksheetSettings.Edit_Readonly);

// Make writable
sheet.SetSettings(WorksheetSettings.Edit_Readonly, false);

Range Read-Only

Make a range of cells read-only via the range instance:

var range = sheet.Ranges["A1:D10"];
range.IsReadonly = true;

Custom Cell Body and Read-Only

Custom cell bodies (like buttons, checkboxes, etc.) are automatically disabled when their owner cell is read-only. This behavior is controlled by the DisableWhenCellReadonly property:

public class MyCustomCell : CellBody
{
    // Override to keep the cell body active even when the cell is read-only
    public override bool DisableWhenCellReadonly => false;
}

Exception Handling

When code attempts to modify a read-only cell, ReoGrid throws specific exceptions:

Handle these exceptions:

try
{
    sheet["A1"] = "new value";
}
catch (CellDataReadonlyException ex)
{
    Console.WriteLine($"Cannot modify cell at {ex.CellPos}: cell is read-only");
}
catch (RangeContainsReadonlyCellsException ex)
{
    Console.WriteLine($"Range {ex.Range} contains read-only cells");
}

Common Patterns

Template with Editable Areas

Create a form template where only specific cells are editable:

var sheet = grid.CurrentWorksheet;

// Set up the template with labels
sheet["A1"] = "Name:";
sheet["A2"] = "Email:";
sheet["A3"] = "Phone:";

// Make the label cells locked
sheet.Cells["A1"].IsLocked = CellLock.Locked;
sheet.Cells["A2"].IsLocked = CellLock.Locked;
sheet.Cells["A3"].IsLocked = CellLock.Locked;

// Explicitly unlock the input cells
sheet.Cells["B1"].IsLocked = CellLock.Unlocked;
sheet.Cells["B2"].IsLocked = CellLock.Unlocked;
sheet.Cells["B3"].IsLocked = CellLock.Unlocked;

// Lock the worksheet — only B1:B3 remain editable
sheet.IsLocked = true;

// Optionally auto-move to unlocked cells
sheet.Options.AlwaysMoveSelectionToUnlockedCell = true;

Related Topics

• Cell Editing — Cell edit behavior
• Worksheet Settings — All worksheet settings
• Data Validation — Validate user input