RadGridView added 2 Command Buttons each row want to disable after one is selected on selected row.

using System;
using System.Collections.Generic;
using Telerik.WinControls;
using Telerik.WinControls.UI;

namespace GUI {
  public partial class FormTest : RadForm {
    // example entity class
    private class MyEntity {
      public string SomeValue      { get; set; }
      public string SomeOtherValue { get; set; }
      public string State          { get; set; }
      // if you only want to check if the entry is deleted use this instead:
      // public bool   SetForDeletion { get; set; }
    }

    public FormTest() {
      InitializeComponent();
    }

    // add the load event to your form
    private void FormTest_Load(object sender, EventArgs e) {
      InitGV();
    }

    #region === GRIDVIEW ==========================================================================
    #region --- init gridview ---------------------------------------------------------------------
    private void InitGV() {
      // add your columns
      GridViewTextBoxColumn col1 = new GridViewTextBoxColumn();
      col1.FieldName  = "SomeValue";
      col1.Name       = "SomeValue";
      col1.HeaderText = "Some Value";

      GridViewTextBoxColumn col2 = new GridViewTextBoxColumn();
      col2.FieldName  = "SomeOtherValue";
      col2.Name       = "SomeOtherValue";
      col2.HeaderText = "Some Other Value";

      GridViewTextBoxColumn col3 = new GridViewTextBoxColumn();
      col3.FieldName = "State";
      col3.Name      = "State";
      col3.IsVisible = false; // hidden from user

      // if you want to use the boolean flag instead (see MyEntity class above):
      //GridViewCheckBoxColumn col3 = new GridViewCheckBoxColumn();
      //col3.FieldName = "SetForDeletion";
      //col3.Name      = "SetForDeletion";
      //col3.IsVisible = false; // hidden from user

      GridViewCommandColumn col4 = new GridViewCommandColumn();
      col4.FieldName      = "Delete";
      col4.Name           = "Delete";
      col4.HeaderText     = "Delete Entry";
      // if you have an image for the button, set it:
      //col4.Image          = myImageSource;
      //col4.ImageAlignment = System.Drawing.ContentAlignment.MiddleCenter;
      //col4.UseDefaultText = false;

      GridViewCommandColumn col5 = new GridViewCommandColumn();
      col5.FieldName      = "UnDelete";
      col5.Name           = "UnDelete";
      col5.HeaderText     = "UnDelete Entry";

      GridViewCommandColumn col6 = new GridViewCommandColumn();
      col6.FieldName      = "OtherButton";
      col6.Name           = "OtherButton";
      col6.HeaderText     = "Whatever may happen here";

      gv.MasterTemplate.Columns.AddRange(
        col1,
        col2,
        col3,
        col4,
        col5,
        col6
      );

      // load gridview data (example)
      List<MyEntity> entities = new List<MyEntity>() {
        new MyEntity() { SomeValue = "My first entry",  SomeOtherValue = "This is some other value" },
        new MyEntity() { SomeValue = "My second entry", SomeOtherValue = "asdf" },
        new MyEntity() { SomeValue = "My third entry",  SomeOtherValue = "jmfpfa" },
        new MyEntity() { SomeValue = "My fourth entry", SomeOtherValue = "wskjdowjdfßp" },
        new MyEntity() { SomeValue = "My fifth entry",  SomeOtherValue = "ewjwoiedjoi" },
        new MyEntity() { SomeValue = "My sixth entry",  SomeOtherValue = "random stuff" }
      };

      gv.DataSource = entities;

      // clear selection
      gv.ClearSelection();
      gv.CurrentRow = null;

      // wire gridview events
      gv.CommandCellClick   += new CommandCellClickEventHandler(gv_CommandCellClick);
      gv.ViewCellFormatting += new CellFormattingEventHandler(gv_ViewCellFormatting);
    }
    #endregion
    #region --- command cell click ----------------------------------------------------------------
    private void gv_CommandCellClick(object sender, EventArgs e) {
      string columnName = (e as GridViewCellEventArgs).Column.Name;
      MyEntity myEntity = (sender as GridCellElement).RowInfo.DataBoundItem as MyEntity;

      switch (columnName) {
        case "Delete":      Delete(myEntity); break;
        case "UnDelete":    UnDelete(myEntity); break;
        case "OtherButton": SomeOtherFunction(myEntity); break;
      }

      // invalidate the current row to trigger ViewCellFormatting for it
      (e as GridViewCellEventArgs).Row.InvalidateRow();
    }
    #endregion
    #region --- command: delete -------------------------------------------------------------------
    private void Delete(MyEntity myEntity) {
      // do something with your entity
      // ...
      // set its state to deleted
      myEntity.State = "DEL";
      // or the boolean flag:
      // myEntity.SetForDeletion = true;
    }
    #endregion
    #region --- command: undelete -----------------------------------------------------------------
    private void UnDelete(MyEntity myEntity) {
      // reset its state
      myEntity.State = "";
      // or the boolean flag:
      // myEntity.SetForDeletion = false;
    }
    #endregion
    #region --- command: some other function ------------------------------------------------------
    private void SomeOtherFunction(MyEntity myEntity) {
      // do something with your entity
      // ...
    }
    #endregion
    #region --- view cell formatting --------------------------------------------------------------
    private void gv_ViewCellFormatting(object sender, CellFormattingEventArgs e) {
      // add all properties which you change in this formatting method here
      // in order to reset their flags for all non-affected cells
      e.CellElement.ResetValue(LightVisualElement.EnabledProperty, ValueResetFlags.Local);

      // now format the cells to your liking
      if (e.RowIndex == -1) {
        // format header cells: e is GridHeaderCellElement
        // ...

      } else if (e.ColumnIndex > -1) {
        // format data cells: e is GridDataCellElement etc.

        // get the current row item as it is easier to work with
        MyEntity myEntity = e.Row.DataBoundItem as MyEntity;

        if (e.Column.Name == "Delete") { // e.CellElement.ColumnInfo is GridViewCommandColumn
          // enable the delete button depending on the state of the item
          e.CellElement.Enabled = myEntity.State != "DEL";
          // instead of using MyEntity you can also check the corresponding cell value directly:
          // e.CellElement.Enabled = e.Row.Cells["State"].Value != "DEL";
            
          // and when checking the boolean flag:
          // e.CellElement.Enabled = myEntity.SetForDeletion;
          // or the corresponding cell directly:
          // e.CellElement.Enabled = e.Row.Cells["SetForDeletion"].Value;
        }
      }
    }
    #endregion
    #endregion
  }
}

        private void Delete(MyEntity myEntity)
        {
            // do something with your entity
            // ...
            // set its state to deleted
            myEntity.State = "DEL";
            // or the boolean flag:
            // myEntity.SetForDeletion = true;
            if (this.radGridView1.CurrentRow!=null)
            {
                  this.radGridView1.CurrentRow.InvalidateRow();
            }

        }