public async void Form1_LoadAsync(object sender, EventArgs e) { var result = await RB.ShowResourceDataAsync(); ResourceDataGrid.DataSource = result; var project = await PB.ShowProjectDataAsync(); ProjectDataGrid.DataSource = project; var projectNameOnly = await RAB.ShowProjectNameOnlyAsync(); this.SelectProCmbBox.SelectedIndexChanged -= new System.EventHandler(this.SelectProCmbBox_SelectedIndexChangedAsync); SelectProCmbBox.DataSource = projectNameOnly; SelectProCmbBox.DisplayMember = "ProjectName"; SelectProCmbBox.ValueMember = "ProjectID"; SelectProCmbBox.SelectedIndex = -1; this.SelectProCmbBox.SelectedIndexChanged += new System.EventHandler(this.SelectProCmbBox_SelectedIndexChangedAsync); var projectNameOnly2 = await RAB.ShowProjectNameOnlyAsync(); this.ChoosePrjNameCmbBox.SelectedIndexChanged -= new System.EventHandler(this.ChoosePrjNameCmbBox_SelectedIndexChangedAsync); ChoosePrjNameCmbBox.DataSource = projectNameOnly2; ChoosePrjNameCmbBox.DisplayMember = "ProjectName"; ChoosePrjNameCmbBox.ValueMember = "ProjectID"; ChoosePrjNameCmbBox.SelectedIndex = -1; this.ChoosePrjNameCmbBox.SelectedIndexChanged += new System.EventHandler(this.ChoosePrjNameCmbBox_SelectedIndexChangedAsync); var projectNameOnly3 = await RAB.ShowResourceNameOnlyAsync(); this.ChooseResNameCmbBox.SelectedIndexChanged -= new System.EventHandler(this.ChooseResNameCmbBox_SelectedIndexChangedAsync); ChooseResNameCmbBox.DataSource = projectNameOnly3; ChooseResNameCmbBox.DisplayMember = "Name"; ChooseResNameCmbBox.ValueMember = "ResourceID"; ChooseResNameCmbBox.SelectedIndex = -1; this.ChooseResNameCmbBox.SelectedIndexChanged += new System.EventHandler(this.ChooseResNameCmbBox_SelectedIndexChangedAsync); }